Select the correct answer. which expression is equivalent to this polynomial? x2 + 12 a. ( x 2 ⁢ 3 i ) ⁢ ( x − 2 ⁢ 3 i ) b. ( x 6 i ) ⁢ ( x − 6 i ) c. ( x 2 ⁢ 3 ) 2 d. ( x 2 ⁢ 3 ) ⁢ ( x − 2 ⁢ 3 )