How many RNA polymerases are present in bacteria that catalyses transcription of all types of RNA ?

Single RNA polymerase .

The correct answer is Option (3)- Single RNA polymerase .

In bacteria, the process of transcription, which involves the synthesis of RNA from a DNA template, is typically carried out by a "Single RNA polymerase."

In bacteria, there are three major types of RNAs: mRNA (messenger RNA), tRNA (transfer RNA), and rRNA (ribosomal RNA). All three RNAs are needed to synthesise a protein in a cell. The mRNA provides the template, tRNA brings aminoacids and reads the genetic code, and rRNAs play structural and catalytic role during translation. There is single DNA-dependent RNA polymerase that catalyses transcription of all types of RNA in bacteria. RNA polymerase binds to promoter and initiates transcription (Initiation).

Therefore, the correct answer in this context is "Single RNA polymerase," which is capable of transcribing all types of RNA molecules in bacterial cells.