When i try to run the below given code i get a keyError. Why is that?

import nltk
import numpy as np
import pandas as pd
from nltk.stem import WordNetLemmatizer
from sklearn.feature_extraction.text import CountVectorizer
from sklearn.metrics.pairwise import cosine_similarity

# Load data from a CSV file into a Pandas DataFrame
open('/Users/kk/Documents/Python Programs/admissions_data.csv')
admissions_df = pd.read_csv('/Users/kk/Documents/Python Programs/admissions_data.csv')

# Preprocess data using NLP techniques
lemmatizer = WordNetLemmatizer()
def preprocess(text):
    tokens = nltk.word_tokenize(text.lower())
    lemmas = [lemmatizer.lemmatize(token) for token in tokens]
    return ' '.join(lemmas)

# Use CountVectorizer to convert text to a matrix of word counts
vectorizer = CountVectorizer(preprocessor=preprocess)
text_matrix = vectorizer.fit_transform(admissions_df['text'])

# Use cosine similarity to find the most similar questions to a user's query
def get_most_similar(query):
    query_vector = vectorizer.transform([query])
    similarity_scores = cosine_similarity(query_vector, text_matrix)
    most_similar_index = np.argmax(similarity_scores)
    return admissions_df.loc[most_similar_index, 'response']

# Build the chatbot using NLTK and the preprocessed data
pairs = [(preprocess(q), preprocess(r)) for q, r in zip(admissions_df['question'], admissions_df['response'])]
chatbot = nltk.chat.util.Chat(pairs)

# Define a function that uses the chatbot to answer user queries
def admissions_chatbot():
    print("Welcome to the college admissions chatbot. How can I assist you today?")
    while True:
        user_input = input()
        if user_input.lower() == 'quit':
            break
        else:
            response = get_most_similar(user_input)
            if response:
                print(response)
            else:
                print(chatbot.respond(user_input))


if __name__ == "__main__":
    admissions_chatbot()

Traceback (most recent call last):
  File "/Users/kk/Library/Python/3.9/lib/python/site-packages/pandas/core/indexes/base.py", line 3802, in get_loc
    return self._engine.get_loc(casted_key)
  File "pandas/_libs/index.pyx", line 138, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/index.pyx", line 165, in pandas._libs.index.IndexEngine.get_loc
  File "pandas/_libs/hashtable_class_helper.pxi", line 5745, in pandas._libs.hashtable.PyObjectHashTable.get_item
  File "pandas/_libs/hashtable_class_helper.pxi", line 5753, in pandas._libs.hashtable.PyObjectHashTable.get_item
KeyError: 'text'

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/Users/kk/Documents/Python Programs/Chatbot V4.py", line 23, in <module>
    text_matrix = vectorizer.fit_transform(admissions_df['text'])
  File "/Users/kk/Library/Python/3.9/lib/python/site-packages/pandas/core/frame.py", line 3807, in __getitem__
    indexer = self.columns.get_loc(key)
  File "/Users/kk/Library/Python/3.9/lib/python/site-packages/pandas/core/indexes/base.py", line 3804, in get_loc
    raise KeyError(key) from err
KeyError: 'text'

You're referencing a column admissions_df['text'], and Python is telling you it does not exist. Try running admissions_df.columns to check what the columns is actually called