The monomers of nylon$-6, 6$ $(X)$ and terylene $(Y)$ are

• A
  Nylon$-6, 6$ $(X)$: $H_2N-(CH_2)_5-CH_3$,$HOOC-(CH_2)_4-CH_3$; Terylene $(Y)$: $HO-CH_2-CH_3$,$HO-C_6H_4-COOH$
• B
  Nylon$-6, 6$ $(X)$: $H_2N-(CH_2)_4-NH_2$,$HOOC-(CH_2)_4-COOH$; Terylene $(Y)$: $HO-CH_2-CH_2-OH$,$C_6H_4(COOH)_2$ (ortho)
• C
  Nylon$-6, 6$ $(X)$: $H_2N-CH_2-COOH$,$H_2N-(CH_2)_5-COOH$; Terylene $(Y)$: $HO-CH_2-CH_2-OH$,$HO-C_6H_4-COOH$
• D
  Nylon$-6, 6$ $(X)$: $H_2N-(CH_2)_6-NH_2$,$HOOC-(CH_2)_4-COOH$; Terylene $(Y)$: $HO-CH_2-CH_2-OH$,$HOOC-C_6H_4-COOH$ (terephthalic acid)