Assign to each of the following differential equations the integrating factor/s (if there are any listed, multiple answers possible).
A) (1 + y^2)/x^2 + y′ = 0 I) μ = 1/(1 + y^2)
B) y/(4 + x) + y′ = 0 II) μ = 1/y
C) 1 + (1 + x)yy′ = 0 III) μ = 4 + x
A= I
B= III
C= II