Classify the function as linear or quadratic and identify the quadratic linear and constant terms

A. Quadratic function; quadratic term: -12x^2; linear term:-6x; constant term:-12
B. Linear Equation; linear term: x; constant term: -12
C. quadratic function; quadratic term: 6x^2; linear term: x; constant term:-12
D. Linear Function; linear term: 6x^2; constant term:-12