Poly-$\beta$-hydroxybutyrate-co-$\beta$-hydroxyvalerate $(PHBV)$ is a copolymer of . . . . . .

• A
  $3$-hydroxybutanoic acid and $4$-hydroxypentanoic acid
• B
  $2$-hydroxybutanoic acid and $3$-hydroxypentanoic acid
• C
  $3$-hydroxybutanoic acid and $2$-hydroxypentanoic acid
• D
  $3$-hydroxybutanoic acid and $3$-hydroxypentanoic acid