The equation $x \frac{d x}{d y}+y=c,$ where $c$ is a constant, represents a family of

(A) exponential curves

(B) parabolas

(C) circles

(D) hyperbolas

The equation $x \frac{d x}{d y}+y=c,$ where $c$ is a constant, represents a family of

(A) exponential curves

(B) parabolas

(C) circles

(D) hyperbolas

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