Final answer:
Both DNA and RNA polymerases share the ability to recognize promoter sequences option (a), a critical step for initiating their respective processes of replication and transcription.
Step-by-step explanation:
Among the functions common to both DNA and RNA polymerases, the correct option is A. Can recognize promoter sequences.
Both types of polymerases have domains that aid in the recognition of promoter sequences. For example, in E. coli, the sigma factor is responsible for helping RNA polymerase locate the promoter sequence where transcription begins. In DNA replication, DNA polymerases also require a specific sequence to initiate synthesis but rely on other proteins such as primase to initially recognize these sites and lay down RNA primers.
While there are differences between DNA and RNA polymerases, the ability to recognize promoter sequences is essential for their function.