In this task, you are given a context and four options. Each option is a suggested ending for the context. You should read the context and pick the best ending for the context. Please answer with "A", "B", "C", and "D".

[Q]: [header] How to buy a light kit for photography [title] Make a list of required and/or desired criteria for your light kit. [step] These features include whether you want lights arranged on the floor or ceiling, what kind of photography you will be doing, how many lights you will need, etc. [substeps] Floor studio lights and backgrounds can be transported and arranged on stands or supports. <sep> (A) You may want several different lighting items in one kit. There are many available but most of the light hardware items, like dimmer switches and binders or small set of battery-powered lights, should be picked up at a craft store. (B) Pointed, straight, or one-sided lights can be divided into categories and arranged on tables or on poles. [title] Purchase fixtures that fit the gender and the type of lighting and coloring range that you want to consider. (C) Ceiling lights are more expensive and must be on a rail system for positioning in a rectangular area while background rollers are mounted on the ceiling. Your type of photography can determine how much light you need. (D) Frame sizes can be adjusted to your personal preference depending on the size of your studio. Don't forget to read the product description as well.
[A]: C

[Q]: [header] How to find out if a good friend is crushing on you [title] Pay attention to their posture when you're around. [step] If your friend is crushing on you, their body language will probably be more open, and they will usually stand with their body turned towards yours, even in a group. [substeps] If your friend has a relaxed posture, with their torso facing towards you, it's a sign that they feel at ease. <sep> (A) If their shoulders are hunched, they may be pressed against you. If they'll just stand in silence, it's a sign that they're not interested. (B) It may mean they like you or it may just mean they are comfortable being around you. Watch for signs that your friend's posture has changed around you. (C) They may also be putting down their phone or tapping their feet. [title] Observe how they look around you when talking to others. (D) They may look up at you a few times throughout a conversation and nod or smile occasionally to show that they trust you. [title] Pay attention to their general body language.
[A]: B

[Q]: [header] How to make a fireplace more energy efficient [title] Install a top-sealing chimney damper. [step] Top-sealing dampers replace the fireplace throat damper and are installed at the top of the chimney. The top-sealing damper has a seal that acts like a storm door, keeping the expensive conditioned air inside the house and the outside air-outside. <sep> (A) [substeps] Check the quality of the damper accurately to ensure its old-fashioned texture. Chimney damper versions range from cheap to premade fireplace damper. (B) [substeps] Most water-based fireplaces end with a top-sealing damper damper. This damper exists because the chimney chimney damper is dry enough to withstand collecting ashes and the chimney damper cannot insulate the poisonous air inside. (C) If you have trouble shooting fire, you could use your fireplace damper to replace the chimney damper's damper. [substeps] A top-sealing damper damper can be found at most home improvement stores. (D) This principle works year-round, whether you're heating or cooling your house. This product can be purchased online and is easily installed by either a homeowner or a handyman.
[A]:
D