Neap tides, relatively weak tides, occur when the moon is in position(s)
a) a.
b) b.
c) a and c.
d) b and d.

Answer: Option D) B and D.

Explanation:

Neap tides are the weak tides which occur when the gravitational forces of the sun and moon are perpendicular to each other and thus, cancels each other out.The tidal range of neap tides is moderate.Neap tides occur twice a month during the first and third quarters of the moon.In the given diagram, Position A corresponds to the new moon.Position B corresponds to first quarter.Position c corresponds to New moon.Position D corresponds to the third quarter.

Thus, it is the position B and D of the moon where the neap tides occur.