Answer: D. 2:1
Step-by-step explanation:
The torque ratio expresses the ratio of the output torque to the input torque.
Given : Input torque= 5 pound - feet
Output torque : 10 pound-feet
Torque ratio is given by :-
![\frac{\text {output torque}}{\text {input torque}}]()
Putting in the values we get:
Torque ratio=

Thus the torque ratio is 2: 1