The substitutability of a particular good/service can play havoc on a company's sales. This is formally defined as elasticity of a good/service. The elasticity/substitutability changes for 4 reasons. The 4 reasons are stated below, briefly describe/explain them.
a) The larger the time interval
b) Broader definition
c) Depends on the size relative to a person's budget
d) The more the good/service is a necessity