Use the intermediate value theorem to show that the polynomial f(x)= x + 2x - 6 has a real zero on the interval [1,2] Select the correct choice below and, if necessary, fill in the answer box(es) to complete your choice.

O A. The polynomial has a real zero on the given interval, because f(1) = and f(2)= are both negative

OB. The polynomial has a real zero on the given interval, because f(-x) has variation(s) in sign

OC. The polynomial has a real zero on the given interval, because f(1) = and f(2) are complex conjugates.

OD. The polynomial has a real zero on the given interval, because f(1) = and f(2)= are outside of the interval

O E. The polynomial has a real zero on the given interval, because f(1) = and f(2)= are opposite in sign

OF. The polynomial has a real pero on the given interval, because f(1) = and f(2)= are both positive