the answer is definitely A.
<span>B. If the temperature of a solid is increased, the solid expands and its volume increases.</span>
<span>We know , E = kQ/r^2 where q = charge and r is separation between point and point charge.
Now, At P, E= kQ/r^2
Since, Q can't be changed, we can do that by varying r
2E = 2kq/r^2
2E = kq/ (r/ sqrt2)^2
Hence, if we bring Q closer such that distance between P and Q becomes r/ sqrt 2, E will get doubled.</span>