Consider the following four statements $(a-d)$ and select the option which includes all the correct ones only $:-$
$(a)$ Lipids are generally water insoluble.
$(b)$ The $R$ group could be a methyl $(-CH_3)$ or ethyl $(-C_2H_5)$ or higher number of $-CH_2$ groups ($1$ carbon to $19$ carbons) in fatty acids.
$(c)$ Palmitic acid has $16$ carbons including the carboxyl carbon.
$(d)$ Arachidonic acid has $21$ carbon atoms including the carboxyl carbon.

• A
  Statement $(a), (b)$ and $(c)$
• B
  Statement $(a), (b)$ only
• C
  Statement $(c), (d)$ only
• D
  Statement $(a), (c)$ and $(d)$