Answer:
Option 3rd is correct
$2.5 is the constant of proportionality in cost per pup cake
Explanation:
The direct proportionality states that:

then the equation is in the form of :
....[1]
where, k is the constant of proportionality.
As per the statement:
The table shows how much Jake charged for the last 4 orders of pup cakes.
Let y represents the cost and x represents the pup-cakes
Consider any values of x and y from the given tables.
x = 3 and y = $7.5
To find constant of proportionality in cost per pup cake.
Substitute these in [1] we have;

Divide both sides by 3 we have;
2.5 = k
or
k = 2.5
Therefore, $2.5 is the constant of proportionality in cost per pup cake