Which of the following statement of a bacterial cell is/are correct?
  1. Mesosome is formed by the extensions of plasma membrane into the cell.
  2. The pili are elongated tubular structures made up of a protein.
  3. Flagellum is composed of filament, hook and basal body.
  4. Ribosomes are about 30 nm by 50 nm in size.

A. (i), (ii), (iii)

B. All of the above

C. (ii) & (iv)

D. None of the above

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