Please help me I dont understand this difficult question :( its worth lots of points!!!

Jessica is selling books during the summer to earn money for college. She earns a commission on each sale but has to pay for her own expenses.

After a month of driving from neighborhood to neighborhood and walking door - to door, she figures out that her weekly earnings are approximately a linear function of the number of doors she knocks on.

She writes the equation of the function like this: E(x) = 10 x - 30 , where x is the number of doors she knocks on during the week and E(x) is her earnings for the weeks in dollars.

Which of the following are reasonable interpretations of the y-intercept of Jessica's function?.

Check all that apply

A. Her expenses are $30 per week.

B. If she does not knock on any doors at all during the week she will loose $30.

C. She will loose $10 per week if she does not knock on any doors

D. She can earn $10 a week even if she does not knock on any doors.