According to the first condition, Andrew is at the leftmost end.
The third condition states that Boom is between Andrew and Carry, so the arrangement looks like:
Andrew, Boom, Carry
The second condition says that there are 3 people between Carry and Garry, so the arrangement expands to:
Andrew, Boom, Carry, (3 people in between), Garry
Since there are 7 people in total, Garry must be at the rightmost end.
The correct answer is (d) Garry.