Correct option is (B) 10
First 10 odd natural numbers are 1, 3, 5, ......., 19.
\(\therefore\) Mean of first ten odd natural numbers \(=\frac{1+3+5+....+19\,(odd)}{10}\)
\(=\frac{(1+19)+(3+17)+(5+15)+(7+13)+(9+11)}{10}\)
\(=\frac{5\times20}{10}\) = 10
Hence, the mean of first ten odd natural numbers is 10.
