(He)...favourite subject is...
His favourite subject is Science.
(We)...favourite subject is...
Our favourite subject is Music.
(She)...favourite subject is...
Her favourite subject is History.
(You)...favourite subject is...
Your favourite subject is maths.
(I)...favourite subject is...
My favourite subject is English.
(They)...favourite subject is...
Their favourite subject is PE.
(She)...favourite subject is...
Her favourite subject is Geography.
(He)...favourite subject is...
His favourite subject is Art.
(I)...favourite subject is...
My favourite subject is Literature.
(It)...favourite subject is...
Its favourite subject is IT.