Answer:
B) x^2/12 +y^2/16 = 1
Explanation:
The distance from focus to covertex is the same as the distance from the center to the vertex: 4. So, the Pythagorean theorem tells you ...
a^2 + 2^2 = b^2
a^2 +4 = 4^2 = 16
a^2 = 16 -4 = 12
So, the standard-form equation ...
x^2/a^2 +y^2/b^2 = 1
looks like this when the values are filled in:
x^2/12 +y^2/16 = 1