Question

select the best way to punctuate the natural pause in the sentence below.
hector finds it hard to concentrate in math class especially when he is hungry for lunch.
hector finds it hard to concentrate . . . in math class especially when he is hungry for lunch.
hector finds it hard to concentrate in math class, especially when he is hungry for lunch.
hector finds it hard to concentrate in math class especially when—he is hungry for lunch.
hector finds it hard to concentrate, in math class especially when he is hungry for lunch.

Explanation:

The natural pause occurs before the dependent clause "especially when he is hungry for lunch" which adds extra information to the main clause. A comma is the correct punctuation to set off this non-restrictive parenthetical phrase. Ellipses (...) are used to show omitted text, em dashes (—) are for abrupt breaks, and placing a comma after "concentrate" incorrectly splits the main clause.

Answer:

B. Hector finds it hard to concentrate in math class, especially when he is hungry for lunch.