Question: What law required that a pub offer at least one beer from a brewery it wasn't tied to?

Is "The landlord of a tied pub may be an employee of the breweryin which case he/she would be a manager of a managed house, or a self-employed tenant who has entered into a lease agreement with a brewery, a condition of which is the legal obligation (trade tie) only to purchase that brewery's beer." the correct answer?
Options are:
[a]. yes
[b]. no
[b].