Which statement is true about the expression

3b+5 and 2b+15+b

a) they are equivalent only when b=0

b)they are equivalent only when b=5

c)they are equivalent only when b=3

d) they are equivalent for any value of b

Dana wants to identify the favorite professional baseball team of people in her community. she stands outside a local sporting goods store and asks every other person who enters, "what is your favorite professional baseball team? " will the results of her survey be valid? explain.