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 sentence has a dependent clause ("especially when he is hungry for lunch") following an independent clause. A comma is needed before the dependent clause to mark the natural pause, and this placement is grammatically correct. The other options use incorrect punctuation: em dashes are unnecessary here, ellipses incorrectly break the main clause, and the comma after "concentrate" misplaces the pause.

Answer:

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