While strains are common in the Sprains frequently occur in the
area.
A. elbow; hamstring
B. wrist; knee
c. knee; back
D. wrist; back

Option A ankle ; hamstring

ie strain is to hamstring and sprain is to ankle.

Explanation:

A sprain is an injury to the ligaments( a muscular  tissue that connects bones together) causing either a partial tear or a complete tear on the fiber bands of the ligament.  Sprains usually occur during activity or sporting exercise and the site for common occurrence are the ankle other areas include elbow, knee and wrist ( where bones are joined together.)

While a strain occurs when the muscle stretches or tears due to injury during an acrivitystrain is an injury to a muscle or tendon which mostly occurs at area around the lower back. Eg hamstring.