The answer is C. 1/9
To find the reciprocal you need to make the numerator the denominator and the denominator the numerator, once you do this you get your answer.
So we need to make 9 a fraction, well 9 is equal to the fraction 9/1.
So all we do is flip it which is 1/9 and there's your answer!
Hope this helped! Have a great day!