Final answer:
The main three stock characters in Commedia dell'Arte are Masters, Servants, and Lovers. From the options provided, 'Masters' and 'Servants' are correct. 'Pets' and 'Directors' do not represent traditional stock characters of this genre.
Step-by-step explanation:
The question refers to the classic stock characters found in Commedia dell'Arte, a form of theatre that originated in Italy in the 16th century. These characters are primarily categorized into three main groups: Masters, Servants, and Lovers (not mentioned in the options). The 'Masters' are often depicted as either foolish or clever old men, the 'Servants' (or 'Zanni') are usually cunning servants who help or hinder the lovers and masters, and the Lovers are the beautiful young people who are in love.
In the context of Commedia dell'Arte, the correct characters from the options provided would be: B. Masters and C. Servants. Option A, Pets, and Option D, Directors, are not traditional stock characters in this form of theatre.