Answer
(c)
Here the smaller prefix is nano. The correct answer is option (c)
Work Step by Step
(a) micro - $10^{-6}$
(b) centi - $10^{-2}$
(c) nano - $10^{-9}$
(d )milli - $10^{-3}$
So, the smallest metric prefix is (c) nano.
You can help us out by revising, improving and updating this answer.
Update this answerAfter you claim an answer you’ll have 24 hours to send in a draft. An editor will review the submission and either publish your submission or provide feedback.