Find the equation of parabola whose vertex is (4,2) and focus is (6,2)?

Question

$\begin{array}{1 1}(a)\;(y-3)^2=8(k-4)\\(b)\;(y-2)^2=8(k-4)\\(c)\;(y-2)^2=4(k-4)\\(d)\;(y-2)^2=6(k-4)\end{array}$