Question #N162

The author of the article, a renowned expert in climate science, argued that the effects of climate change are *already* being felt by many parts of the world, and that, if not addressed, these effects *will continue to grow* more severe.

Which choice best combines the underlined portions of the passage into a single, correctly punctuated sentence?
A. already being felt by many parts of the world, and that, if not addressed, these effects will continue to grow more severe.
B. already being felt by many parts of the world, and if not addressed, these effects will continue to grow more severe.
C. already being felt by many parts of the world, and that if not addressed, these effects will continue to grow more severe.
D. already being felt by many parts of the world, and that if not addressed, these effects will continue to grow more severe.