Point A is at a lower electrical potential than point B. An electron between them on the line joining them will A. Move towards A B. Move towards B C. Move at right angles to the line joining A and B D. Remain at rest

The correct answer is A. Move towards A.

An electron is a negatively charged particle. In an electric field, negative charges are attracted to positive charges and repelled by other negative charges. Therefore, if point A is at a lower electrical potential than point B, an electron between them on the line joining them will move towards A.

Option B is incorrect because an electron will be repelled by point B, which has a higher electrical potential. Option C is incorrect because an electron will not move at right angles to the line joining A and B. Option D is incorrect because an electron will not remain at rest.