Identify the 16th term of a geometric sequence where a1 = 4 and a8 = -8,748.. -172,186,884. -57,395,628. 57,395,628. 172,186,884.

First, determine the common ratio by the equation,
                                an = a1 x r^(n - 1)
Substituting the values,
                           -8748 = 4 x r^(8 - 1) 
The value of r is -3. By the same equation, the 16th term is,
                                 a16 = 4 x (-3)^(16 - 1)
                                 a16 = -57,395,628
Thus, the answer is the second choice.