$(a)\;2 \sqrt {\tan x}+\frac{2}{5}(\tan x )^{5/2} +c \qquad(b)\;2 {\tan x}+\frac{2}{5}(\tan x )^{5/2} +c \qquad(c)\;2 \sqrt {\tan x}+\frac{2}{5}(\tan x )^{3/2} +c \qquad (d)\;2 \sqrt {\tan x}+\frac{2}{5}(\tan x )^{7/2} +c$