The uniform tank of weight W is suspended by means of a cable, of length l, which

Question:

The uniform tank of weight W is suspended by means of a cable, of length l, which is attached to the sides of the tank and passes over the small pulley located at O. If the cable can be attached at either points A and B, or C and D, determine which attachment produces the least amount of tension in the cable. What is this tension?
Given:
W = 200 lb
l = 6 ft
a = 1 ft
b = 2 ft
c = b
d = 2a