Correct answer: CThe direct answer is option C, 3. Begin by expanding the square: (x^6−2)^2=x^12−4x^6+4. Substitute this into M(x): M(x)=x^12−4x^6+4−(x^12−4x^6)+9x^3. The x^12 terms cancel, and the −4x^6 terms also cancel. Thus M(x)=9x^3+4. Its highest non-zero power is x^3, so its degree is 3. Option A, 12, ignores the cancellation of the x^12 terms. Option B, 6, ignores that the x^6 terms also cancel. Option C is correct because 9x^3 remains and 9 is non-zero. Option D, 0, would apply only to a non-zero constant polynomial, but 9x^3 is present. The important lesson is that degree must be found after simplifying completely; one must not choose the largest exponent visible in the unsimplified expression. Memory cue: expand, combine like terms, cancel, and only then read the highest power.