The correct option is
B 20
Series I= 2,6,12 and Series II = 30,20,12
If we observe series (2,6,12----), the 2 consecutive numbers increment in the following pattern +4,+6..We can predict the pattern to continue as +4,+6,+8,+10 etc..Hence, the numbers in the series will be
2,6,12,20,30....If we observe Series 2,the numbers decrement in the pattern -10,-8 ...Hence we can predict the pattern to continue as -10,-8,-6,-4 etc..Hence, the numbers in the series will be
30,20,12,6,2......
Hence, option 'C' is correct.