Final answer:
The 7th term in the geometric sequence with the given formula is calculated to be 31250, which does not match any of the provided choices.
Step-by-step explanation:
The 7th term in the geometric sequence described by the explicit formula a_n=2×5(n−1) can be found by substituting n with 7:
a_7=2×5(7−1) = 2×5(6) = 2×56 = 2×(15625) = 31250
So, the correct answer is not among the provided choices (A. 80, B. 160, C. 320, D. 640), indicating there may be either a typographical error in the question or the choices provided.