Statement: Researcher Jiankui's claim that he has changed the human fetal genes has proved to be true.

Choose one of the following options

A - statement is definitely true.

B - The statement is probably true.

C - Statement can not be determined.

D - The statement is definitely false.

Which of the following element is 21th from right end of the series?

Select the number from among the given option that can replace the question mark (?) in the following series.

17, 18, 22, 31, 47, 72, ?

If 3792 = 39 and 7242 = 22, then 2958 = ?

Arrange the words in the alphabetical order and pick the one that come at second last.

Select the option that is related to the third number in the same way as the second number is related to the first number.

25: 633 :: 34 : ?

Which of the following is the ninth to the right of the 20th element from right end of the above arrangement.

Find the missing alphabet:

D J O ? V X

Consider the following number sequence:

4 3 4 5 7 3 9 3 5 7 5 4 7 8 9

____ and ____ live adjacent to C.