Answer: Python Puzzler #1508

The answer is B. The program prints:

4
8
12
16

Why?

% gives the remainder after dividing. A remainder of 0 means the number divides exactly by 4, so the program prints the multiples of 4 up to 16.

Trace table

A trace table follows the program step by step. Here’s this one:

number	number % 4	printed?
1	1
2	2
3	3
4	0	yes
5	1
6	2
7	3
8	0	yes
9	1
10	2
11	3
12	0	yes
13	1
14	2
15	3
16	0	yes

The code again

for number in range(1, 17):
    if number % 4 == 0:
        print(number)