If you raise 4 to the 214th power what is the units digit

4²¹⁴.
Note that if the exponent is ODD , the unit digit is always 4:
4¹ = 4,  4³ = 64,  4⁵ = 1024 ... 4¹⁵ = 1,073,741,824, etc.
But when the exponent is EVEN, the last digit is always 6:
4² = 16,  4⁶ = 4,096,  4⁸ = 65,536, ...4¹⁶ = 4,294,967,296

By induction we can say that the last digit of 4²¹⁴ is 6, because the exponent is EVEN

D) the x-intercept represents adam's commission pay when he had zero total sales

The correct answer is: b