Two spherical,nonconducting,and very thin shells of uniformly distributed positive charge $Q$ and radius $d$ are located a distance $10d$ from each other. $A$ positive point charge $q$ is placed inside one of the shells at a distance $d/2$ from the center,on the line connecting the centers of the two shells,as shown in the figure. What is the net force on the charge $q$?

• A
  $\frac{qQ}{361\pi \varepsilon_0 d^2}$ to the left
• B
  $\frac{qQ}{361\pi \varepsilon_0 d^2}$ to the right
• C
  $\frac{362qQ}{361\pi \varepsilon_0 d^2}$ to the left
• D
  $\frac{360qQ}{361\pi \varepsilon_0 d^2}$ to the right