C: y = 6x+20
Let's construct our own equation and then see if one of the available options matches.
"During her storefront shift, she sells her pizzas at a rate of 6 pizzas per hour"
This sounds like the equation should be:
6x
Since for every hour (represented by x) she sells 6 pizzas. Now we have:
"During her delivery shift, she sells 20 pizzas per night."
Notice that there's no mention of anything per hour. If she does the delivery shift, she sells a constant 20 pizzas. So let's modify our equation to:
6x + 20
And since we want it in slope intercept form, let modify a bit further:
y = 6x + 20
Now look at the available options and see if there's anything that matches. And there is ... Option C is a perfect match.
