<P> In mathematics, two variables are proportional if a change in one is always accompanied by a change in the other, and if the changes are always related by use of a constant multiplier . The constant is called the coefficient of proportionality or proportionality constant . </P> <Ul> <Li> If one variable is always the product of the other and a constant, the two are said to be directly proportional . x and y are directly proportional if the ratio y / x is constant . </Li> <Li> If the product of the two variables is always a constant, the two are said to be inversely proportional . x and y are inversely proportional if the product xy is constant . </Li> </Ul>

Which of the following graphs represent y as directly proportional to x