Frankie Sparks and the Class Pet

The best thing ever is happening in Frankie Sparks’s third grade class: They are getting a class pet! Their teacher, Miss Cupid, tells them they will vote on their pet, but it has to meet some “parameters.” Their pet must:
1. Fit in aquarium.
2. Cost less than $50.
3. Be easily portable.
4. Be able to be left alone for the weekend.
Frankie thinks that a rat—just like the rats in her beloved Aunt Gina’s lab—would be the perfect fit. But her best friend, Maya, doesn’t think a rat would be great at all. They are kind of gross and not as cool as a hermit crab, which is Maya’s top choice. Using her special workshop, can Frankie find a way to convince her teacher and her best friend that Team Rat is the way to go?