Answer:
phrases B and C are variables.
Explanation:
Any thing whose value can be changed is called variable.
Whereas, if the value is fixed then it is called a constant.
We can use these definitions to find the phrases that contains a variable.
First option is: A three cups of salsa - It is constant because, the number of cups of salsa is fixed which is 3.
Second option is: the weight of the puppy - It is variable because, the weight of the puppy can be changed and not always fixed.
Third option is : the cost the of dinner- It is variable because, the cost of the dinner can be changed and depends on the quantity of the food ordered.
Last option: twenty feet of wire: It is a constant because the length of the wire is fixed which is 20 feet.
Therefore, the phrases B and C are variables.