Which of the following sentences uses parallel structure?

Ithink it's a. but i could be wrong because it might be b. but it's not the other two

1vertical line 2 vertical lines 2 vertical lines 1 vertical line 1 horizontal line1 vertical line 2 vertical lines 2 vertical lines 1 vertical line 1 horizontal line1 vertical line 2 vertical lines 2 vertical lines 1 vertical line 1 horizontal line1 vertical line 2 vertical lines 2 vertical lines 1 vertical line 1 horizontal line1 vertical line 2 vertical lines 2 vertical lines 1 vertical line 1 horizontal line1 vertical line 2 vertical lines 2 vertical lines 1 vertical line 1 horizontal line