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 develop a friendly tone of voice [title] Breathe from your diaphragm to control your voice. [step] Making your tone of voice friendlier requires you to be aware of how fast you talk and how high and low your voice gets. Use strong breaths from your abdomen for better control. <sep> (A) [substeps] To vary the focus on your voice, your diaphragm should be placed directly below the point of exhalation. Say " inhale ", " exhale ", and then " breathe ". (B) [substeps] This technique is also called dog breathing. During this breathing, make sure to breathe from your diaphragm, not the back of your throat where your vocal chords are. (C) [substeps] To check if you're breathing from your diaphragm (the muscle that sits right below your lungs), watch yourself in the mirror while you breathe in. If your shoulders and chest rise, you're taking shallow breaths without using your diaphragm. (D) [substeps] If you need to slow down the pace of your speaking, suck your breath in, narrowing your throat so that it's at a 90 degree angle against your ribcage. Gently inhale and release air through your nostrils so that it's drawn down between them.
Output:
C