Select the number from among the given option that can replace the question mark (?) in the following series.

1.6, 2.3, 3, 3.7, 4.4, 5.1, 5.8, 6.5, ?, 7.9, 8.6

Given: 1.6, 2.3, 3, 3.7, 4.4, 5.1, 5.8, 6.5, ?, 7.9, 8.6

​Logic: Difference of two constitutive number is increasing from 0.7

1.6+0.7=2.3

2.3+0.7=3

3+0.7=3.7

3.7+0.7=4.4

4.4+0.7=5.1

5.1+0.7=5.8

5.8+0.7=6.5

7.2+0.7=7.9

7.9+0.7=8.6

So, ? is replaced by 7.2

Thus, Option B is the correct answer.