Chemists use letters of the alphabet as for the elements.

The symbol is the right answer.

Explanation:

The “ Symbol” is the correct answer because chemist uses the letters of the alphabet to denote the element. For instance, the element oxygen is denoted by the letter of the alphabet “O”, the hydrogen is denoted by the letter of alphabet “H”, Boron is denoted by the letter of alphabet “B”, etc. Here these are the examples that use one letter but there are other elements that use more than 1 letter as the symbol. For example, the Chlorine is represented by the Cl.

answer; i believe that the correct answer is (a) potassium(k)

increased stability in the completion of fluorine's outer shell.