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".

Ex Input:
[header] How to tell the difference between different types of plant fertilizers [title] Use soluble fertilizer when you want to water in the fertilizer. [step] This fertilizer is usually added to the watering can. [substeps] This is best for helping boost growth when its growing season and for frequently fed container plants. <sep> (A) In the summer break, try adding two or three inches of food to fill the watering can-too much fertilizer will kick in when the corn is thirsty, too little will only keep it growing. Plan it out in a bucket or basin for easy irrigation. (B) [title] Use a hose to water a potted plant after planting. [step] Water a cactus when they get too hot for watering. (C) Leaves that don't bond and stink up the water are also large fertilizer that needs to be added to your watering can. [title] Use different types of fertilizer. (D) [title] Use granular fertilizer when you need to supply a concentrated amount of nutrients. [step] A plant may be lacking in a particular nutrient (this will be evident through such things as yellow leaves, , etc.

Ex Output:
D

Ex Input:
[header] How to exercise to prevent blood clots [title] Get up and move around. [step] Whether you're traveling by train, plane, or automobile, long-distance travel involves a lot of sitting. When you sit, you decrease circulation in your legs-especially if you sit with your legs crossed or with one foot under you. <sep> (A) If you are on a train or coach, the seat underneath you always feels flat, as if you are sitting. While there are good ways to stretch out your legs, there is not a lot a group of people can do. (B) This will help promote blood circulation to your feet. It will also keep you from rubbing your legs in an annoying manner-you can't promote blood flow when you're sitting on one leg. (C) [substeps] You can exercise while you drive or driving, although getting up and down on the exercise train can significantly improve circulation. You can also listen to music while you exercise, which will also help to prevent blood clots. (D) [substeps] If you're on a plane, try to get an aisle seat so you can get up and move around more easily. Ideally, you want to get up and stretch your legs or walk up and down the aisle once every hour or so.

Ex Output:
D

Ex Input:
A person grabs a saddle from the side of a barn. They carry it and put it onto a horse. they <sep> (A) climb onto the back of the horse and ride off. (B) hold up a trophy of achievement. (C) also put saddle shoes on a horse who walks around. (D) remove the saddle from the horse and tie it.

Ex Output:
A