Consider the following sentences (A) and (B) about motions of the Earth and…

Earth has two primary motions: rotation, its spin about its own axis (producing day and night, one rotation taking about 24 hours), and revolution, its orbit around the Sun (producing the seasons, one revolution taking about 365¼ days). The Earth's rotational axis is not perpendicular to its orbital plane — by standard convention it makes an angle of about 66½° with the plane of the orbit, equivalently about 23½° with the perpendicular (normal) to that plane. These two figures are complementary (66½° + 23½° = 90°), and this fixed inclination of the axis is what produces the seasonal variation as the Earth revolves.

Statement (A), ‘Rotation is the movement of the earth on its axis,’ is exactly this standard definition, so (A) holds. Statement (B) gives the angle between the axis and the orbital plane as 33½°, but the accepted figure is 66½° (or 23½° measured from the perpendicular), not 33½°; the number in (B) does not match either of the two standard complementary figures, so (B) does not hold.

• ‘Only (B) is correct’ would require the wording of (A) to be flawed, but “movement of the earth on its axis” is precisely the standard definition of rotation, so there is no basis to rule (A) out.

• ‘Both (A) and (B) are correct’ accepts the 33½° figure at face value without checking it against the standard 66½°/23½° pair, so it misses that the number quoted in (B) is wrong.

• ‘Both (A) and (B) are incorrect’ additionally rejects (A), which is a standard, accurate definition, so ruling it out as well is unjustified.

So (A) is a correct, standard definition while the specific angle in (B) is a factual error — only (A) is correct.