But what if I did a harder option/elective than other people?
All good, you are set. If you are doing an Option, an additional process called Optional Question Scaling is applied. If the option/elective you have done has been deemed more difficult based on the marks of the entire cohort, the mark for that option is scaled to even the playing field. For example, if it is deemed that English Advanced Students who studied a specific text performed to a lower standard, those students’ marks are scaled up."
Source: How does scaling work