The answer is B. The program prints:
4

Why?
count goes through the string and counts how many times ‘o’ appears.
Trace table
A trace table follows the program step by step. Here’s this one:
| letter | matches? |
|---|---|
| r | |
| o | yes |
| b | |
| o | yes |
| t | |
| (space) | |
| r | |
| o | yes |
| b | |
| o | yes |
| t |
The code again
word = "robot robot"
print(word.count("o"))
Try it: change one number in the program and predict the new output before you run it.