Identify the correct statements from the following:
$(i)$ The skin is the main physical barrier.
$(ii)$ Mucus coating of the epithelium lining the respiratory,gastrointestinal,and urogenital tracts is a physiological barrier.
$(iii)$ $IgA, IgM, IgE, IgG$ are types of $T$-cells.
$(iv)$ The primary immune response is very intense.

• A
  Only $(i)$
• B
  Only $(iii)$
• C
  Only $(iii)$ and $(iv)$
• D
  Only $(i)$ and $(ii)$