Answer:
See below.
Explanation:
This problem and the answers don't work.
The way the problem is written, the answer is 17 km.
There is no such answer.
There is a mistake somewhere.
If the man is walking at the speed of 3/4 km/h, then in 30 minutes, which is half of 1 hour, he walk 3/8 km. There is no answer of 3/8 km in the choices.
Please check on the problem and post it correctly.