Complete the following series questions by finding the missing letters out of given alternatives:

RPN, TTM, VXK, XBH, ?

Which two letters will come in place of question mark? Choose from the given alternatives.

Which two letters will come in place of question mark? Choose from the given alternatives.

Which two letters will come in place of question mark? Choose from the given alternatives.

Which two letters will come in place of question mark? Choose from the given alternatives.

Which two letters will come in place of question mark? Choose from the given alternatives.

Which two letters will come in place of question mark? Choose from the given alternatives.

Which letter will come in place of the question mark? Choose from the given alternatives.

Direction: In the following question, one term in the number series is wrong. Find out the wrong term.

$105,85,60,30,0,-45,-90$