In the following examples, name the factor that affects demand and describe it's impact on your demand for a new cell phone.
a. You hear a rumor that a new and improved model of the phone you want is coming out next year
b. your grandparents give you $500
c. a cellular network announces a holiday sale on a text message package that includes the purchase of a new phone
d. a friend tells you how great his new cell phone is and suggests that you get one, too.