Final answer:
Both conjugation and transduction are proven methods that can spread genes, including those for antibiotic resistance, acquired by transduction or temperate phage in bacteria. Conjugation involves direct cell-to-cell transfer, while transduction is mediated by bacteriophages.
Step-by-step explanation:
In bacterial gene transfer, transduction is the method by which genes acquired by infection with a temperate phage can be spread, specifically through the actions of bacteriophages. Transduction involves a virus (bacteriophage) that transfers genes. A virus can mistakenly package bacterial DNA into its viral capsid and transfer this DNA to another bacterium upon infection. If the transferred genes include those for antibiotic resistance, transduction can thereby facilitate the spread of resistance among bacteria.
Conjugation, on the other hand, is a mechanism of direct gene transfer between bacteria using a pilus, which creates a physical bridge between two bacterial cells. Conjugation allows for the transfer of plasmids, which can contain antibiotic resistance genes; thus, it significantly contributes to the spread of antibiotic resistance within a bacterial population.
Transformation involves the uptake of free DNA from the environment by bacteria. While this method can also spread antibiotic resistance genes, it is not typically associated with the spread of genes acquired specifically by transduction or temperate phage infection.
Therefore, the correct answer to the question is: D) Both A and C, meaning both conjugation and transduction are proven methods that spread genes acquired by transduction or infection with a temperate phage.