I was going to say:
Pronouns and/or be/have/do are occasionally omitted in spoken English at the beginning of the sentence.
But then I thought, I don't have any particular sentence in mind here. So it must be a. But then I looked into the rules:
to generalize about a whole class or species, usually of plants or animals. A singular noun is used for this purpose. The first example means ‘The elephant species is hunted.’
The elephant is still hunted for its tusks.
The snowdrop is the first flower to arrive in the new year.
Well, it says, "usually of plants or animals," but I have a reason to think the usage occasionally extends beyond the outlined limits. That is, the is sometimes used to mean something general. A class of something, one of a class of something. Which overlaps with usage of a.
And even if we take the previous sentence, I could probably say "with the usage of a" to mean a general action, could I?