This is easy but i can’t figure it out

Mary just sent out invitations to her wedding last week the invitations were so heavy that she put more than just one stamp on each envelope she used 255 stamps and mailed out 85 invitations and see you as an equal amount of stamps on each envelope

Believed that natural laws could be used to define economic systems

Which verb form correctly completes this sentence? me gusta leer el género narrativo, por eso prefiero que los libros novelas policiales. a. seas b. sean c. seamos d. sea