Final answer:
H₂O (water) is the covalent compound among the options as it involves the sharing of electrons between nonmetals, unlike the ionic compounds listed.
Step-by-step explanation:
The covalent (molecular) compound among the options given is H₂O (water). The rest of the compounds listed (NaCl, CaCl2, and KBr) are ionic compounds, which are formed between metals and nonmetals where electrons are transferred from one atom to another.
A covalent compound like H₂O, on the other hand, is made up of nonmetals, and the atoms share electrons rather than transfer them.