Answer: Python Puzzler #860

The answer is C. The program prints:

**
**
**
**

Why?

The outer loop runs 4 times (one per row). Inside it, the inner loop adds 2 symbols to line. So you get 4 rows of 2.

Trace table

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

row	line printed
0	**
1	**
2	**
3	**

The code again

for row in range(4):
    line = ""
    for col in range(2):
        line = line + "*"
    print(line)