Only answer if you're very good at math. Please I keep on posting this but nobody is helping me. What is the 4th term of the expansion of (1 - 2x)^n if the binomial coefficients are taken from the row of Pascal's triangle shown below?

1 6 15 20 15 6 1

A: 240x^4

B: 160x^3

C: -160x^3

D: -20x^3​