Answer:
c. They may remain in possession after the sale
Step-by-step explanation:
When a landlord wants to sell a property that is currently occupied by tenants, it must notify both the tenants and potential buyers about the rental agreement and his/her intention to sell the property.
Generally speaking, once rental agreements are signed, they are independent from who actually owns the property (house, apartment, office, etc.). Even if the buyer of the house (new owner) doesn't want the tenants to stay, the tenants have the right to do so until their contract expires.
The tenants have the right to even limit and set the conditions by which the seller can show the property, e.g. if they don't want to, the owner cannot cannot take pictures of the property's interior if the tenants consider that it violates their privacy.
If the buyer wants to rent the property, it is generally a good thing to have tenants with valid contracts.