There are three unchanged identical metallic spheres `1,2 and 3` each of radius `r` and are placed at the verticles of an equlilateral triangle of side `d`.A charged metallic sphere having equal `q` of same radius `r` is touched to sphere `1` after some time it is taken to the location of sphere `2` and is touched to it ,then it is taken far away form sphere `1,2,3` after that the sphere `3` is grounded the charge on sphere `3` is (neglect electrostatic induction by assuming `d gt gt 2r)`

Options

A. zero
B. `(-3qr)/(4d)`
C. `(-qr)/(2d)`
D. `(-qr)/(2d)`

Answer

2

Explanation

`V=(1)/(4piepsilon_(0))(3Q)/(2R)`