Select the noun phrase to complete the sentence. a total solar eclipse can last up only to 7.5 minutes a - but has many dramatic effects. b- , which surprises many people. c- , a relatively short time period. d- in total duration.

C-, a relatively short time period.

A noun phrase is a phrase which has a noun or a pronoun as the nucleus and, gramatically, functions as a noun.

Considering this, we can conclude that the correct answer is C: "a relatively short time period" because the nucleus of that phrase is the noun "period".

The rest are not possible options because both A and B are independent clauses which do not complete the sentence but add new independent information, and D is not a noun phrase.

c, his tragic flaw to cause his downfall