1.  Choose the correct alternative that will continue the same pattern and replace the question mark in the given series : 11, 10, ?, 100, 1001, 1000, 10001

A. 101
B. 110
C. 111
D. None of these

Answer: Option A

Explanation:

The pattern is - 1, x 10 + 1, - 1, x 10 + 1, - 1, x 10 + 1, .....

So, missing term = 10 x 10 + 1 = 101.