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a, b and c are the first three terms of a geometric series. If the harmonic mean of a and b is 12 and that of b and c is 36, then the first five terms of the series are:

A

`n(n+1)`

B

`n^(2)`

C

`n(4-n)`

D

`n(6-n)`

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The correct Answer is:
A
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