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 find electrons [title] Obtain a periodic table of elements. [step] This is a color-coded table that organizes all the known elements by atomic structure. Each element has a 1 , 2, or 3-letter abbreviation and is listed along with its atomic weight and atomic number. <sep> (A) [substeps] Periodic tables can easily be found in chemistry books and online. [title] Find the element in question on the periodic table. (B) You can obtain this table by purchasing an periodic table from a department store or buying it online. [title] Enter the atom and element number into a set of figures. (C) This list must match or exceed 1 , 024 atoms. [substeps] Finding the ratio of atomic weight to atomic mass can be tricky, especially if there are not any known atomic weight units. (D) [title] Multiply the atomic weight by multiplication. [step] You need to multiply it by the atomic mass in that atom to find electrons.
A