Option B.
5x−2)(4x^2−3x−2)
=(5x+−2)(4x^2+−3x+−2)
=(5x)(4x^2)+(5x)(−3x)+(5x)(−2)+(−2)(4x^2)+(−2)(−3x)+(−2)(−2)
=20x^3−15x^2−10x−8x^2+6x+4
=20x^3−23x^2−4x+4