Which of the following is $NOT$ an example of a synthetic detergent?

• A
  $CH_{3}-(CH_{2})_{11}-C_{6}H_{4}-SO_{3}^{-}Na^{+}$
• B
  $CH_{3}(CH_{2})_{16}COO^{-}Na^{+}$
• C
  $[CH_{3}(CH_{2})_{15}-N(CH_{3})_{3}]^{+}Br^{-}$
• D
  $CH_{3}(CH_{2})_{16}COO(CH_{2}CH_{2}O)_{n}CH_{2}CH_{2}OH$