Which of following phrases could be used as a basis for a short story?
the life story of a famous musician
a championship basketball game in which a new player is the star
a family mix-up over selecting a birthday present for dad
an account of three generations of a british family in india
settling the first earth colony on another planet
the mysterious disappearance of a cake from the pantry

I would say that all scenarios that are not too complex could be a basis for a short story, but also in principle,  you could shorten and simplify any story to make a short story out of it!

So there is no clear distinction.

But among the options, the better candidates are:

a championship basketball game in which a new player is the star
a family mix-up over selecting a birthday present for Dad
the mysterious disappearance of a cake from the pantry

The other options are potentially too complex.

The answer would be b .