The answer would be C.
On the line, the medium would be 81.5.
This eliminates answer choice A since 82+83/2=82.5.
This leaves B and C.
Then the lower quartile should equal to 77.
The answer is not B since the lower quartile would be 76.
Leaving Answer choice C as the correct answer. Also if you check, the lower quartile for the numbers provided would be 77.