The Mass of a Human Leg Below the Knee Is

The mass of a human leg below the knee is 0.60 of the mass above the knee, and its centre of mass is located at 0.3 of the length of the lower leg from the knee joint. When the leg is bent from straight to a right angle at the knee, by what amount does the centre of mass of the leg shift? Express your answer in terms of the length of the leg below the knee.

A) 0.68
B) 0.50
C) 0.38
D) 0.11