Complex conjugate root theorem question

Hi,

"In mathematics, the complex conjugate root theorem states that if P is a polynomial in one variable with real coefficients, and a + bi is a root of P with a and b real numbers, then its complex conjugate abi is also a root of P."

Based on above theorem, how come below answer is not (B) a-bi.

Am I missing something?



View attachment 34193
Because the coefficients are not real!
 
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