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". 

[header] How to get rid of the whitefly [title] Vacuum the flies. [step] Use a small hand vacuum, or hold the furniture-cleaning nozzle of a standard vacuum cleaner. Walk around your infested plants and suck the pests from the undersides of the leaves and foliage. <sep> (A) This method is quick and straightforward, and it can remove whiteflies from all stages of the development cycle-from larvae to mature, plant-munching adults. Vacuuming is most effective as soon as you notice an infestation. (B) [substeps] Lice/hornets that have infested the insect where possible will probably cause an infestation when they have access to this species. Lice and hornets can be pregnant bees or even cobwetters. (C) [substeps] Once you've vacuumed up all of the insects, you can dismantle the insect and wash it off. Plant diseases like freeze burn-gas are very likely to have mites, fungus, or other biological problems with this insect. (D) [substeps] If possible, clean the potted plants as a habit to keep the insects away. [title] Tear off the hard outer leaves once the insects have died.
A

[header] How to make green beans [title] Bring a pot of water to a boil in a saucepan over medium-high heat. [title] Add salt to the water once it begins to boil. [title] Trim the stems of the green beans and place them into the pot of gently boiling water. <sep> (A) [title] Once the water boils, drop 1-inch (2.5 centimeter) stems of 1 1/2 pounds (2.35 grams) of green beans into the boiling water. [title] Wait until the green beans are ready to be processed. (B) [step] You will need one green bean per cup (260 ml) of boiling water. [title] Add the green beans to the pot. (C) [title] Add ground bell pepper, thyme, and basil to the water for the next step. [step] Stir the green beans in with the salt until everything is evenly combined and the bean pieces are tender to the touch. (D) [title] Leave the green beans in the pot for 4 or 5 minutes, until they are cooked but still crisp. [title] Drain the green beans and cover them in ice water to stop the cooking process.
D

[header] How to cook beef joint [title] Buy your beef joint according to how you want to cook it. [step] Tender cuts of meat, like sirloin and fore rib, are better for roasting, while leaner cuts of meat, like topside and silverside, are better for braising. [title] Pick out a fresh cut of beef. <sep> (A) [step] When purchasing beef, make sure the meat is a deep, dark red. Look for beef containing little streaks of fat throughout leaner muscle, and with an outside layer of firm, creamy-white fat. (B) [step] Choose a cut of beef that's still fresh but that's not dripping any liquid. Remove any fat, and dice the beef till it's sweet-smelling. (C) [step] You can get the joint from your local butcher's store if you're not planning on braising it yourself. Think about purchasing very fresh cuts of beef, then pick the one that matches your braising preferences. (D) [step] For example, tenderloin or prime sirloin are flat cuts of beef. This helps prevent overcooking, for example, by roasting for a minimum of 30 minutes.

A