Scarlett is $42$ years old. She works for a local radio station. Which of the following income she earns does not constitute income from trade?

a$.$

Overtime pay of R$20000$ from her employer

b$.$

Bi$-$weekly wages of R$7000$ from her employer

c$.$

Profits from hairdressing business of R$2000$

d$.$

Interest income of R$30000$ from her investment