Detailed Instructions: 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". 
Problem:[header] How to make paint colors [title] Gather paint-mixing supplies. [step] You'll need a palette and a paint knife or brush in order to get started. Mixing paint with a paint knife results in a more even, uniform color compared to a brush. <sep> (A) To prepare a painting surface, you'll need a bucket or a palette. You'll also need a measuring stick. (B) [substeps] If you're using brushes to mix paint, make sure to clean them in between mixing. You don't want paint of a previous color mixing with the two you are currently mixing. (C) [substeps] A palette knife is a lighter brush that comes in a few different colors and has two handles. The knife is considered safe for use with paint, although there is a high possibility of getting paint on your fingers by breaking a glass, cutting a wax paper, wiping the mirror down, or even washing the brush. (D) If you want a more vibrant, richer tone, you'll need to buy a small amount of paint. Therefore, a palette knife or brush would work well.
Solution:
B