Final answer:
d) piRNAs (piwi-interacting RNAs) are the small RNAs that suppress transposon movement in germ lines, essential for genetic stability in reproduction.
Step-by-step explanation:
The small RNAs that suppress transposon movement in germ lines are d) piRNAs (piwi-interacting RNAs). Unlike other small RNAs such as miRNAs (microRNAs) that regulate gene expression by interfering with the expression of certain mRNA messages and are commonly 21 to 24 nucleotides in length, piRNAs are slightly longer and are specifically involved in the silencing of transposable elements within the germ cells. This suppression is crucial for maintaining the stability of the genetic information passed through generations. PiRNAs work together with Piwi proteins to form a complex that identifies and silences transposon mRNA, preventing their movement and potential harmful effects on the genome.