Answer:
Option B is correct.
Step-by-step explanation:
Given Sequence is:
4 , -8 , 16 , -32 , ...
To find: Explicit formula for the sequence.
From give sequence,

Option A :


of the sequence does not matches with the
of the formula.
Thus, This option is incorrect.
Option B :





of the sequence matches with the
of the formula.
Thus, This option is correct.
Option C :


of the sequence does not matches with the
of the formula.
Thus, This option is incorrect.
Option D :


of the sequence does not matches with the
of the formula.
Thus, This option is incorrect.
Therefore, Option B is correct.