Answer:
c)They can also be simultaneous in S if their separation is zero.
Step-by-step explanation:
By relativity theory, we can say two events when seen from two different reference frames can only be simultaneous when they are at the same space location and occur simultaneously in at least one reference frame, therefore when Frame S′ usually passes Frame S. Two occurrences in S′ are simultaneous, therefore these occurrences can be simultaneous in S when their separation is 0 (that is they are at the same location)
And therefore option c. If their separation is zero, they can also be simultaneous in S.