We say that the design of a study is biased if
a. the sample isn’t perfectly representative of the population.
b. you get a sample result that differs from the true value.
c. it is very likely to underestimate or very likely to overestimate the value you want to know.
d. the correlation is greater than 1 or less than –1.
e. an observational study was used when an experiment would have been feasible.

A) the sample isn't perfectly representative of the population.

Explanation:

in this scenario it would be the consumer demand as most influential in making the decision. the band members need to figure out where and from whom they will make the most money, in other words who out of the two consumer groups - football fans or car drivers - will spend their money, who is more likely to contribute to their cause and buy what they are offering.

the branch of biology that deals with the normal functions of living organisms and their parts.

the way in which a living organism or bodily part functions.