For which values of the constants a and $b$ is the differential equation

$(x+y{e}^{\text{a}\text{x}\text{y}})dx+bx{e}^{2xy}dy=0$

an EXACT differential equation?

Select one:

A$.a=1,b=1$

B$.a=1,b=2$

C$.a=2,b=-1$

D$.a=-1,b=2$

E$.a=2,b=1$