Question

which of the following is the medical symbol for before?
o a
o 8
o δ
o σ

Explanation:

In medical notation, "a" (ante - Latin for before) is used to denote "before".

Answer:

There are no correct options provided as the common medical symbol for "before" is "a" (from the Latin "ante"). If we assume the first option "O a" is meant to be "a", then the answer is a.