Well, the diameter of a circle is simply a length, so your measurement will have units of length. We just have to find an answer that has only units of length.
A). gram, second . . . mass and time. That can't be it.
B). kilogram, ampere . . . mass and current. That can't be it.
C). centimeter, meter . . . both lengths. This one is looking good.
D). candela, mole . . . light intensity and some chemical thing. That can't be it.
So it can't be anything else on this list but <em>C</em> .
Natural gas is a fossil fuel<span>, though </span>the<span> global warming </span>emissions<span> from its combustion are </span>much<span> lower than those from coal or oil. </span>Natural gas<span> emits 50 to 60 percent less </span>carbon dioxide<span> (</span>CO2<span>) when combusted in </span>a<span> new, efficient </span>natural gas<span>power plant </span>compared<span> with </span>emissions<span> from </span>a<span> typical new coal plant.</span>
a) Cumulus is 100% the correct answer