Let $\vec{F} = \langle a x + b y + 3 z, \, x + c z, \, 7 y + m x \rangle$ where $a, b, c, m$ are constants.

(a) Suppose the flux of $\vec{F}$ through any closed surface is zero. Which of the constants can be determined? Select all that apply.
A. The constant $a$
B. The constant $b$
C. The constant $c$
D. The constant $m$

(b) Suppose instead that the circulation around any closed curve is zero. Then
$b$ =
$c$ =
$m$ =