第1413题：horizontal ellipse

If the major axis of an ellipse is parallel to the x-axis in a rectangular coordinate plane, we say that the ellipse is horizontal. If the major axis is parallel to the y-axis, we say that the ellipse is vertical. In a rectangular coordinate plane, where the center of a horizontal ellipse is (h,k), we have

As pictured a>b where a, one-half of the length of the major axis, is called the major radius. and b, one-half of the length of the minor axis, is called the minor radius. The equaton of this ellipse in standard form follows (  ).

A. $\dfrac{(x+k)^2}{a^2}+\dfrac{(y+h)^2}{b^2}=1$

B. $\dfrac{(x-k)^2}{a^2}+\dfrac{(y-h)^2}{b^2}=1$

C. $\dfrac{(x+h)^2}{a^2}+\dfrac{(y+k)^2}{b^2}=1$

D. $\dfrac{(x-h)^2}{a^2}+\dfrac{(y-k)^2}{b^2}=1$

From 《Advanced Algebra》 , chapter 8