Catechol is a chemical present in several fruits. The enzyme catechol oxidase can oxidise catechol into a quinone. Catechol oxidase is inhibited by parahydroxybenzoic acid (PHBA), which has a structure similar to catechol. When PHBA is present, the Michaelis-Menten constant ($K_m$) of catechol oxidase increases. In what way does PHBA inhibit catechol oxidase?
- A1, 2 and 3
- B1 only
- C2 only
- D3 only