A Woman at a Point a on the Shore of a Circular

A woman at a point A on the shore of a circular lake with radius 4 mi wants to arrive at the point C diametrically opposite on the other side of the lake in the shortest possible time.She can walk at the rate of 6 mi/h and row a boat at 2 mi/h .How should she proceed? (Find ) .Round the result,if necessary,to the nearest hundredth.

A) 0.44 radians
B) She should walk around the lake from point A to point C.
C) 0.46 radians
D) She should row from point A to point C radians
E) 0.62 radians