Can someone backmeup here

the scatter plot shows the relationship between the average number of nightly customers and the number of months since a restaurant opened. the equation represents the linear model for this data.

y = 5x + 20

what does the number 5 in the equation mean in this context?

the restaurant has been open for 5 months.

there were 5 customers per month after the restaurant was open 120 months.

the average number of customers per night increased by 5 each month.

there were 5 customers per night when the restaurant opened.

for every 5 months the restaurant has been open, there are 120 more customers per night.