To find the number of days \( d \) it will take Mrs. Stevenson to give away all her pencils, we start with the total number of pencils she has (200) and the rate at which she gives them away (5 pencils per day).
The equation we need will express that the total number of pencils she starts with (200) minus the number of pencils she has given away (5 pencils per day times the number of days \( d \)) equals zero when she has given away all the pencils.
So, the correct equation is:
\[ 200 - 5d = 0 \]
This means the correct answer is:
B: \( 200 - 5d = 0 \)