The correct answer is: B. difficult
The word "tedious" means "causing weariness through boredom or lack of interest." A tedious task is one that is long and boring, and requires a lot of effort to complete.
The word "easy" means "not difficult or demanding." An easy task is one that can be completed quickly and without much effort.
The word "tiring" means "causing physical or mental fatigue." A tiring task is one that is physically or mentally demanding, and can leave you feeling exhausted.
The word "troublesome" means "causing problems or difficulties." A troublesome task is one that is difficult to complete, and can cause you problems or difficulties.
In this case, the problem is described as being "tedious to tackle." This means that it is a long and boring task, and requires a lot of effort to complete. Therefore, the correct answer is B. difficult.
