The correct option is B Friday
As today is Tuesday. So the number for Tuesday is 1. Since My uncle will come after 45 days, we have to add 1 to 45 and take the modulo 7, since a week contain 7 days.
46≡4(mod 7), (Since 46-4 = 42 is divisible by 7)
As, 4th day will be the required day. so we will count 4th day keeping number for Tuesday as 1, i.e., Friday.