निम्नलिखित में से कौन सा, उपर्युक्त परिच्छेद का सबसे अधिक तर्कसंगत उपनिगमन (कोरोलरी) है ?

Correct Option: (d) Increasing green cover could trigger the release of carbon trapped in soil

The passage describes how human-made carbon dioxide increases plant and vegetation growth. However, this increased plant growth stimulates microbial activity in the soil through root systems. This heightened microbial activity, in turn, accelerates the decomposition of organic carbon stored in the soil, releasing it back into the atmosphere as carbon dioxide. This creates a feedback loop where trying to increase vegetation (green cover) to absorb carbon dioxide might actually stimulate the soil to release its massive stored carbon. Thus, a direct and logical corollary is that increasing green cover could trigger the release of carbon trapped in soil, as stated in option (d). Option (a) is a generic ecological statement not central to this feedback loop. Option (b) is factually incorrect as carbon dioxide is also released naturally. Option (c) is wrong because plant growth is stimulated by carbon dioxide, not primarily by soil carbon.