You will be given a definition of a task first, then some input of the task.
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 crochet lace [title] Work up a foundation chain. [step] Attach crochet thread to your crochet hook using a slipknot, then work up 21 chain stitches. [substeps] Check the " tips " section for information on making slip knots and chain stitches. <sep> (A) In most cases, stitches are required to go through the foundation chain, not between the chain stitches. To make slip knots, wrap the yarn over the hook twice, then pull the tail through the first stitch, then over the second stitch, the two stitches together. (B) For a more specialized project, select not to repeat this online. With a crochet hook, use your wrist to create a foundation chain (commonly known as a chain stitch). (C) You can vary the length of this foundation chain, but make sure that your chains equal a number divisible by your intended groupings plus one. A standard grouping will be five stitches, so your chain count should be a multiple of five plus one extra : 21 , 26 , 31 , 36, etc. (D) [title] Thread your crochet hook by wrapping yarn. [step] Create an overhand knot with the yarn of your hook.
Output:
C