How many integers from 1 to 100 (both inclusive) have odd number of factors?	Choices: A) 7 B) 8 C) 9 D) 10 E) Greater than 10
All perfect squares have odd # of factors. Squaring integers 1-10 produces 1, 4, 9, 16, ... 100 which all have odd # of factors. Answer is 10
<result>D</result>
How many integers from 1 to 100 (both inclusive) have odd number of factors?