To factor the expression \( 24e + 32f \) using the greatest common factor (GCF), we first need to find the GCF of the coefficients 24 and 32.
The factors of 24 are:
- \( 1, 2, 3, 4, 6, 8, 12, 24 \)
The factors of 32 are:
- \( 1, 2, 4, 8, 16, 32 \)
The greatest common factor of 24 and 32 is 8.
Now, we can factor out 8 from the expression:
\[ 24e + 32f = 8(3e + 4f) \]
This means the factored form of \( 24e + 32f \) is: \[ 8(3e + 4f) \]
So the correct answer is: C. \( 8(3e + 4f) \).