Examples of autotrophic bacteria are: (a) parasites (b) saprophytes (c) pathogenic

(d) chemosynthetic forms.

(d) chemosynthetic forms

Explanation:

Autotrophs are characterized by their ability to produce their own food; parasites, saprophytes, and pathogenic (disease-causing) organisms do not have this ability. Chemosynthetic ones, however, can through the conversion of one or more carbon-containing molecules into organic matter.