Answer:
The correct option is;
The domain, r is equivalent to W = {0, 1, 2, 3,...}
Step-by-step explanation:
The cost for each cup of tea sold by the restaurant = $1.50
The cost per tea refill = $0.50
The amount of tea the restaurant brews = 4 refills per customer
The cost of r tea refills C(r) is given as follows;
C(r) = 0.5·r + 1.5
The domain is the set of all whole, W, numbers or the set of all natural numbers including 0
r = W = {0, 1, 2, 3,...}.