Using the following LP formulation below, which of the following statements is CORRECT.

MAxP$=5x+5Y$

$1x100A$

$1Y80B$

$2x+4Y400C$

$x,Y0$

Constraint $C$ has a slack of $50$

Constraint $B$ is binding

Constraint $B$ has a surplus of $30$

Constraint $B$ has a slack of $30$

Constraint A has a slack of $30$