# Oxidation state of central metal atom in $[C0(NH_3)_5Cl]^{2+}$

$(a)\;+3 \\(b)\;+2 \\(c)\; -3 \\(d)\;-2$

$x+5 \times (0) -1 =+2$
$x=+2+1=3$
Hence a is the correct answer.