Can you explain how to solve such type of Statistics questions?

It would be great help if you can explain variation of such questions as well.

Question 36 Let X1, ...; Xn (n > 2) be a random sample from the distribution of the random Not yet variable X with an exponential distribution with \\underline (mean) 3 > 0: answered Define the following estimators for B: Marked out of 1 31 := 1EL Xi, B2 := EL Xi, and B3 := =X1+ 4X2 P Flag question Which of these estimators are unbiased? Select one: O only 32 O All of them 3, and B3 O None of them Question 37 Let X1. . ..; X, (n > 2) be a random sample from the distribution of the random Not yet variable X with a Poisson distribution with rate A > 0: answered Define the following estimators for A: Marked out of 1 Al := ZEL, X?, 12 := 2 EL Xi, and Ag := =X1+ 2X2 Flag Which of these estimators are unbiased? question Select one: O only 12 O All of them O A, and Ag None of them