I think there's more than one answer for both.
For "a" -- 1 and 3
For "b" -- 1 and 4 (This sentence needs to have "the" in front of "nursery school."
The papayas in our garden were ripe, grandmother usually sent a basket of(a)_____to her friend,Mrs.Ghosh who was the principal(b)_______nursery school.
options::a)1.them
2.it
3.these
4.that
(b)1.of
2.in
3.on
4.for
I THINK A:1
B:of
2 answers
a) them
b) of
b) of