Answer:
<em>The answer to your question is </em><em>c. H2O</em>
Explanation:
<em>a. CaCO3 ----> Calcium Carbonate is obviously not a binary compound because it contains more than two elements. </em>
<em>b. CuSO4 ----> CuSO4 stands for copper(II) sulfate. Sulfate is the polyatomic ion SO4 -2.</em>
<em>c. H2O ----> Binary molecular compounds are composed of only two elements. Examples are H2O, NO, SF6 etc. </em>
<em>d. Pb(NO3)2 ----> Lead(II) nitrate is an inorganic compound with the chemical formula Pb(NO3)2.</em>
<em>I hope this helps and have a great day!</em>