The correct option is C ClO−
(a)ClO−2x−4=−1⇒x=+3The oxidation state of Cl is +3
(b)ClO−3x−6=−1⇒x=+5The oxidation state of Cl is +5
(c)ClO−x−2=−1⇒x=+1The oxidation state of Cl is +1
(d)ClO−4x−8=−1⇒x=+7The oxidation state of Cl is +7
Therefore, the correct option is (c)