Identify the equation as separable, linear, exact, or having an integrating factor that is a function of either x or y alone.
(4x^3 + y)dx + (x + 4y^3)dy = 0
Select all that apply.
A. has an integrating factor ÎĽ(x) or ÎĽ(y) not equal to a constant
B. exact
C. separable
D. linear
E. none of the above