Final answer:
Juliet's concern is for Romeo's safety, fearing the consequences if he's caught by her family. Romeo reassures her by expressing that his love for her outweighs these fears.
Step-by-step explanation:
The concern that Juliet has about Romeo being present is b) Juliet is worried about Romeo's safety, and Romeo promises to protect himself. In the play, Juliet is anxious that if Romeo is found in the Capulet garden, it could lead to his death at the hands of her family members, which signifies her concern for his wellbeing. Romeo responds to this by professing that the love he has for Juliet makes him fearless and that he would rather face death than live without her love.