Answer:
option a is correct
The next term in the sequence -324, 108, -36, 12,..... is -4
Step-by-step explanation:
In Geometric sequences it follows a pattern where the next term is found by multiplying by a constant i,e common ration(r)
For 
Common ratio(r) = 
the formula for nth term of this sequence is given by;

Given the sequence: -324, 108, -36, 12,.....
This sequence is a geomtric sequence with common ratio =
and 
Since,
,
and so on..
We have to find the next term in this sequence i.e, 
Using nth sequence formula:

Therefore, the next term in the sequence -324, 108, -36, 12,..... is -4