According to the play the Duke of Illyria is fa... - JAMB Literature 2021 Question

Option A. The idea of love. 

In the play "Twelfth Night," the Duke of Illyria, Orsino, is initially portrayed as a man deeply in love with Lady Olivia. He spends much of the play expressing his love for her and attempting to win her affection, often through grand declarations of love and romantic poetry and music.

However, as the play progresses, it becomes clear that the Duke's fascination with love is not rooted in his feelings for Olivia specifically, but rather in the idea of being in love itself. He is enamored with the idea of being in love and the romantic feelings it evokes, and seems to be less concerned with the person he is in love with.