Three of the statements are true. 'D' is false.
Glass and rubber are excellent insulators, total duds as conductors.
Manganese has 2 (two) electron that would free floating and able to form a metallic bond.
The electronic configuration of manganese is (Ar) 3d5 4s2. The two electron in 4s orbital are the valence electron which can freely move from one place to another.
I'm assuming we're applying the standard Integral form of the calculation of work. The solution is provided in the image.