In a mature tourist market such as Bellaria there are only two ways hotel owners can increase profits: by building more rooms or by improving what is already there.
Conclusion (it follows that)
Hotel owners cannot increase their profits in Bellaria.
Evidence
In a mature-tourist market such as Bellaria, there are only two ways hotel owners can increase profits: by building more rooms or by improving what is already there.
Rigid land-use laws in Bellaria rule out construction of new hotels or any expansion of hotel capacity.
Evaluate
The blank is prefaced by a Support Indicator, "since", so we know we're trying to supply a missing premise.
The argument is basically saying
What is missing in there? The argument needs to establish that these people won't be able to do either of the two things..
Here, those two things were 1. build more rooms 2. improve what's there
Did the evidence establish that they can't build more rooms and can't improve what's there?
It did half of that. It showed that they can't build more rooms.
Thus, the missing information that would logically complete the argument must indicate that improving existing facilities is not an option.
Goal
Let's find an answer that suggests why improving what is already there is not a feasible option for increasing profits in Bellaria.