(a) A person commits an offense if he commits robbery as defined in Section 29.02, and he:
(1) causes serious bodily injury to another;
(2) uses or exhibits a deadly weapon; or
(3) causes bodily injury to another person or threatens or places another person in fear of imminent bodily injury or death, if the other person is:
(A) 65 years of age or older; or
(B) a disabled person.
(b) An offense under this section is a felony of the first degree.
(c) In this section, "disabled person" means an individual with a mental, physical, or developmental disability who is substantially unable to protect himself from harm.