Answer: d.By naming the different groups he hopes to persuade, Obama builds pressure to support military action and create a unified response to the atrocities.
Explanation:
The sentence that would best add commentary to this paragraph is option D "By naming the different groups he hopes to persuade, Obama builds pressure to support military action and create a unified response to the atrocities".
This can be seen in the text where Obama encourages every Americans to support the military action against Syria and also reiterated his stance on America as "the anchor of security globally and also named different groups to support the action of the military.
