Answer: Python Puzzler #3722

The answer is B. The program prints:

46

This answer was checked by running the program for real.

Why?

The loop remembers the biggest number it has seen so far, and replaces it whenever it finds a bigger one. This is how computers find the maximum.

Trace table

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

n	n > biggest?	biggest
31	yes	31
4	no	31
20	no	31
46	yes	46
10	no	46

The code again

numbers = [31, 4, 20, 46, 10]
biggest = 0
for n in numbers:
    if n > biggest:
        biggest = n
print(biggest)