The preposition "through" indicates movement within or across a place.
In this case, the hunters are moving inside or across the forest.
The correct sentence should be:
"The hunters went through the forest."
Thus, the correct answer is Option A ("through").
Arun’s present age in years is 40% of Barun’s. In another few years, Arun’s age will be half of Barun’s. By what percentage will Barun’s age increase during this period?