The answer is D. The program prints:
oo oo oo oo
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 | oo |
| 1 | oo |
| 2 | oo |
| 3 | oo |
The code again
for row in range(4):
line = ""
for col in range(2):
line = line + "o"
print(line)Try it: change one number in the program and predict the new output before you run it.