Lever is a simple machine that helps in lifting or moving objects with less effort. It consists of a rigid bar or plank that rotates around a fixed point called a fulcrum. There are three types of levers: first-class lever, second-class lever, and third-class lever.

In this question, we are given four objects: scissors, bottle opener, nail cutter, and forceps. We need to identify which of these objects are examples of levers.

(i) Scissors: Scissors consist of two blades joined together at a fulcrum. When we squeeze the handles of the scissors, the blades pivot around the fulcrum, allowing us to cut objects. Therefore, scissors are an example of a lever.

(ii) Bottle opener: A bottle opener is a tool used to remove caps or lids from bottles. It usually has a curved end that acts as a fulcrum, and a handle that provides the effort. By applying force on the handle, we can pry open the bottle cap. Thus, a bottle opener is also an example of a lever.

(iii) Nail cutter: Nail cutter is a tool used to trim fingernails or toenails. It consists of two blades joined together at a fulcrum. By pressing the handles of the nail cutter, the blades pivot around the fulcrum, allowing us to cut nails. Therefore, a nail cutter is a lever.

(iv) Forceps: Forceps are a type of tweezers used in medical procedures or laboratory work. They consist of two arms joined together at a fulcrum. By applying force on the handles, the arms of the forceps can be opened and closed. Forceps can be considered as a type of lever as well.

Based on the explanations above, all four objects - scissors, bottle opener, nail cutter, and forceps - are examples of levers. Therefore, the correct answer is option 'D' - (i), (ii), (iii), and (iv).

Because they are examples of levers