Following are the statements about the prostomium of an earthworm.
$(a)$ It serves as a covering for the mouth.
$(b)$ It helps to open cracks in the soil into which it can crawl.
$(c)$ It is one of the sensory structures.
$(d)$ It is the first body segment.
Choose the correct answer from the options given below.

• A
  $(a), (b)$ and $(c)$ are correct
• B
  $(a), (b)$ and $(d)$ are correct
• C
  $(a), (b), (c)$ and $(d)$ are correct
• D
  $(b)$ and $(c)$ are correct