Which diagram represents the equation for the following problem?

I think of a number, add 8, and then multiply by 3. My answer is 66. What is my number?

A. \( x + 24 = 66 \)
B. \( 3x + 8 = 66 \)
C. \( 3(x + 8) = 66 \)
D. \( 3x + 24 = 66 \)