Final answer:
The three PIWI protein families in Drosophila are Piwi, Aubergine, and Argonaute, which are important for gene regulation involving small RNAs like miRNA and siRNA. option c is answer
Step-by-step explanation:
The three PIWI protein families in Drosophila are Piwi, Aubergine, and Argonaute. These proteins play a critical role in the regulation of gene expression at the post-transcriptional level by interacting with small RNAs such as miRNA and siRNA.
For example, Argonaute proteins are a part of the RNA-induced silencing complex (RISC), which interacts with siRNAs to mediate gene silencing. option c is answer