Can I start a sentence with a singular noun with no article?

For example, which one of the following sentences can I use?

Consumer of Product X needs to fill out a rebate form […].
Consumers of Product X need to […].
A consumer of Product X needs to […].

This is for a general-purpose announcement.

Answer

Countable nouns need an article or similar, if singular:

A consumer will fill out a rebate form.
Each consumer will fill out a rebate form.
The consumer will fill out a rebate form.
My dog ate my homework.

Generics/uncountable nouns need to be used without:

Blood is running through the veins.
Water will be refilled at the next Oasis.