In Which of the Following Will the Least Amount of Force

In which of the following will the least amount of force be necessary to overcome a 20 lb. resistance?

A) angle of pull = 30 ^$\circ$ , effort arm = 3"
B) angle of pull = 45 ^$\circ$ , effort arm = 2"
C) angle of pull = 60 ^$\circ$ , effort arm = 4"
D) angle of pull = 120 ^$\circ$ , effort arm = 1"