The reaction conditions leading to the best yield of `C_(2)H_(5)Cl` are :
A. `C_(2)H_(6)("excess")+Cl_(2)overset("UV light")rarr`
B. `C_(2)H_(6)+Cl_(2)overset("Dark")underset("room temperature")rarr`
C. `C_(2)H_(6)+Cl_(2)("excess")overset("UV light")rarr`
D. `C_(2)H_(6)+Cl_(2)overset("UV light")rarr`