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 build a personal desktop computer [title] Prepare the mainboard (motherboard). [step] If you want to assemble the well-liked device, you should use intel i3, i5, i7 mainboard. [title] Mount the cpu in the socket of the mainboard. <sep> (A) [step] If the motherboard is necessary, you may mount it on the side of the mainboard. [title] Determine if your pc will break in half (eject). (B) [step] You must choose the correct cpu for your motherboard, and install it according to its instructions. [title] Connect the cpu cooler to the mainboard. (C) [step] You should do this with the cable slots facing outward. [title] Add the adapter with cpu attach (within reason). (D) [title] Order the components from the mount bar at the front of the motherboard. [step] Ensure they're all in order properly, and then attach software to the motherboard.
Output:
B