To determine the odd one out from the given sequence, let's analyze the numbers:
6, 9, 15, 21, 24, 28, 30
We can observe that all the numbers in the sequence are either multiples of 3 or multiples of 6. However, the number 28 does not fit this pattern. It is not a multiple of 3 or 6.
Analyzing each option:
A. 28 - This option is incorrect because it is not a multiple of 3 or 6.
B. 21 - This option is correct because it is a multiple of 3.
C. 24 - This option is incorrect because it is a multiple of 6.
D. 30 - This option is incorrect because it is a multiple of 6.
Therefore, the odd one out is option A, 28, as it does not follow the pattern of being a multiple of 3 or 6.