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 treat psoriasis with phototherapy [title] Try uvb phototherapy. [step] There are two different types of ultraviolet b (uvb) phototherapy, home and clinical. Uvb phototherapy is undergone when the light penetrates the skin, which slows down the growth of the skin cells. <sep> (A) [substeps] Uvb phototherapy is much like home therapy. But there are a few modifications that you need to make. (B) The uvb phototherapy process destroys the water and damaged light cells that contaminate the skin, producing melanin and other melancolors. After repeated phototherapy it can delay or interfere with the development of the psoriasis. (C) Uvb phototherapy is more frequently used on those prone to psoriasis than it is for humans. [substeps] Uvb phototherapy does not " shrink " the skin, but it is less likely to damage and degrade your natural psoriasis cells. (D) Whether it is done at home or in a clinic, uvb phototherapy is given for specified periods of time and on a regular schedule. [substeps] The specific time periods and your schedule for this treatment depend on how extensive your psoriasis is and the specific areas of your body that are affected.
Output:
D