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". 

Example Input: [header] How to introduce a pleco to a goldfish tank [title] Ask how large the pleco will grow to be. [step] Although most pet stores will sell plecos that are only a few inches in length, you should know that they can grow quite large. Fully grown plecos can reach up to two feet in length. <sep> (A) [title] Check your tank's surface before you place the pleco into the tank. [step] Make sure that your aquarium is opaque or has a drop-down tray so that your pleco is not exposed to water. (B) This can have a negative impact on their lifespan. [title] Choose a tank with large walls and no air holes. (C) [title] Make sure you cover more than twice the tank. [step] If you find that your pleco grows too much, cover the entire tank with a blanket. (D) The exact size of the pleco will vary depending on the species. Ask someone at the pet store how large the pleco will get before making a purchase.
Example Output: D

Example Input: There's a woman sitting on a cozy chair with her two cats next to her, knitting a black yarn hat. the black cat <sep> (A) wakes up from its sleep, goes over and rubs on the woman several times and one person in the back grabs his cat, drinks some water and finally goes back to sleep. (B) is now sitting on a silver plate, one paw quickly getting knitzed. (C) gives a series of pats on the brown and blue body, while the black cat tries to stand up. (D) is sitting right next to her and playing with the yarn while the brown cat is watching them.
Example Output: D

Example Input: [header] How to care for your chihuahua puppy [title] Feed your puppy a healthy food. [step] Like other puppies, chihuahuas need nutritious diets to keep them healthy. They do not need to be fed a specific diet but you should ask your veterinarian for brand recommendations. <sep> (A) [substeps] Make sure to give your dog low-calorie dog food. The best quality dog food will come from the centers for disease control and prevention (cdc). (B) [substeps] Bars should be formulated in a low protein the most recommended type. Puppy food made specifically for dogs should have 1/8 ounce of quality bar protein per serving. (C) [substeps] Like other small dogs, chihuahuas are at risk of developing heart and kidney problems if they are fed a diet high in salt. Look a dog food that is low in salt to help avoid this issue. (D) [substeps] A well-balanced dog diet has two basic components: high fiber, low fat, and low level of protein. A dog's diet should always be low in protein.
Example Output:
C