xternal-link">c</a></span><span class="op">(</span><span class="st">"Electricity [from Coal]"</span>, <span class="st">"Electricity [from Solar]"</span><span class="op">)</span>, </span>
<span>                                   <span class="fu"><a href="https://rdrr.io/r/base/c.html" class="external-link">c</a></span><span class="op">(</span><span class="st">"Motors -&gt; MD"</span>, <span class="st">"Cars -&gt; MD"</span>, <span class="st">"LED lamps -&gt; Light"</span><span class="op">)</span><span class=