Number Series

Answer : D

Explanation :

The difference between seventh and sixth is 42,
Difference between sixth and fifth is 36,
Difference between fifth and fourth is 30,
between IVth and IIIrd is 24,
between IIIrd and second is 18.
It menas the difference atr in the increasing order of 12,18,24,30,36 and so on and the first term will be 19-12=7