CASSIUS. There’s a bargain made. Now know you, Casca, I have moved already

Some certain of the noblest-minded Romans

To undergo with me an enterprise

Of honourable-dangerous consequence.

–The Tragedy of Julius Caesar,

William Shakespeare

Which statement is the best analysis of what causes Casca to join the conspiracy?

Casca joins the conspiracy because Cassius uses various means to manipulate his emotions.
Casca joins the conspiracy because Brutus has already joined, and he respects Brutus.
Casca joins the conspiracy because Caesar has become king, and he is against this.
Casca joins the conspiracy because Cinna persuades him to trust Cassius.