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 grow asters [title] Prepare the seeds in winter. [step] If you choose to sow seeds indoors, you should do so roughly one to two months before your expected transplant date. [substeps] Note that seed germination tends to be fairly uneven, so do not expect all of the seeds you sow to grow. <sep> (A) Plants require different amounts of time to germinate, so try to choose seeds that will typically be growing in the past week before your transplant date. Monitor the moisture level of the soil in the area during the first few weeks after bringing in a new plant. (B) Since seed germination is so unpredictable, many gardeners prefer to buy seedlings from a garden nursery or to use plants divided from previously established asters. [title] Fill small containers with seed starting medium. (C) Cut small circles out of the soil in order to start seed germination. Pick small, specialized seeds that only sprout when the first frost of the season comes. (D) Control the weather for the season so the plants do not need all of them. It is common for asters to grow in well-drained, colder soil.
B