The correct option is C A combination of Ca(OCl)2, dibasic Calcium hypochlorite - Ca3(OCl)2(OH)4 and dibasic Calcium Chloride - Ca3Cl2(OH)4.
2Ca(OH)2+2Cl2→Ca(OCl)2+CaCl2+2H2O
Dry slaked lime on reaction with chlorine gives Calcium oxychloride also called Bleaching Powder. Do note that Ca(OCl)2 is also called Calcium Hypochlorite.
NaOCl - Sodium hypochlorite, is called liquid bleach. In general, bleaching powder is more stable than NaOCl and also has more available Chlorine. Do note that the term "bleaching powder" is a blanket term. It is not just a simple combination of Calcium hypochlorite Ca(OCl)2, Calcium chloride CaCl2 and Calcium Hydroxide Ca(OH)2. Instead, it consists of Ca(OCl)2 mainly, dibasic Calcium hypochlorite, Ca3(OCl)2(OH)4 and dibasic Calcium Chloride, Ca3Cl2(OH)4.