Given the task definition and input, reply with output. 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 kill weeds [title] Determine the ideal height of your grass. [step] All lawns have an ideal grass height that promotes healthy growth. Depending on climate and geography, your ideal grass height is between 1/4 inch (0.635 cm) and 3 inches (7.62 cm). <sep> (A) Grass heights can vary in different growing techniques, so it's important to measure your lawn's natural slope to determine whether it's level or uneven before you start your weed killer. [substeps] Most weed killers are mild and effective at killing weeds, but more aggressive to different grasses or shrubs. (B) In spite of this, some lawns may not be tall enough to prevent extreme frost. [substeps] A lawn that is not cultivated and maintained can be overgrown. (C) [substeps] Talk to a landscaping expert or a professional at your local home and garden retailer to get an understanding of the type of grass you have and how high it should grow. Keep grass a little bit longer when in doubt. (D) If you live in a temperate climate and consistently maintain a recommended lawn length, then you can calculate your lawn's height without needing to soil surability. [substeps] Make sure you factor in your local regulations when determining the ideal grass height.
C