The Birdnest pre-school is (only held on days with good weather, and not held on days with bad weather. Only rainy days or strong windy days are considered days with bad weather. The wooding of the principal Of the pre-school was held on the last Thursday of July the pre-school was not held on this days.From the data given it can be inferred that the reason for this is.

 There are two tribes, tribe A and tribe B.
 Any woman in any one of the two tribes marries just one man and he is from the other tribe.
 Any man in any one of the two tribes marries just one Woman and she is from the other tribe.
 Mamu is a male and his father belongs to one of the two tribes and his mother belongs to other tribe.

Supposing that male children belong to their father’s tribe and female children belong to their mother’s
tribe, consider the following.
(i) If Mamu’s mother’s brother belongs to tribe A, then Mamu belongs to tribe A.
(ii) If Mamu’s father’s sister belongs to tribe A, then Mamu belongs to tribe A.
(iii) If Mamu has a grandfather belonging to tribe A, then Mamu belongs to tribe A.

Of the above three statements,