How to apply the capitalize with condition?

I'm wondering how to use the capitalize function when another column has a specific value.
For example, I want to change the first letter of students with Master's degree.

# importing pandas as pd 
import pandas as pd 

# creating a dataframe 
df = pd.DataFrame({
    'A': ['john', 'bODAY', 'minA', 'peter', 'nicky'], 
    'B': ['Masters', 'Graduate', 'Graduate', 'Masters', 'Graduate'], 
    'C': [27, 23, 21, 23, 24]
})

# Expected result
#   A   B   C
#0  John    Masters 27
#1  bODAY   Graduate    23
#2  minA    Graduate    21
#3  Peter   Masters 23
#4  nicky   Graduate    24

I tried it like this, but it didn't apply well.

df[df['B']=='Masters']['A'].str = df[df['B']=='Masters']['A'].str.capitalize()

Here is the complete code:

import pandas as pd 

# Creating the DataFrame
df = pd.DataFrame({
    'A': ['john', 'bODAY', 'minA', 'peter', 'nicky'], 
    'B': ['Masters', 'Graduate', 'Graduate', 'Masters', 'Graduate'], 
    'C': [27, 23, 21, 23, 24]
})

# Capitalize column A conditionally based on B
df['A'] = df.apply(lambda row: row['A'].capitalize() if row['B'] == 'Masters' else row['A'], axis=1)

# Display the updated DataFrame
print(df)

Output:

     A         B   C
0   John   Masters  27
1  bODAY  Graduate  23
2   minA  Graduate  21
3  Peter   Masters  23
4  nicky  Graduate  24