If a continuous function `f` defined on the real line `R ,` assumes positive and negative values in `R` then the equation `f(x)=0` has a root in `R` . For example, if it is known that a continuous function `f` on `R` is positive at some point and its minimum value is negative then the equation `f(x)=0` has a root in `Rdot` Consider `f(x)=k e^x-x` for all real `x` where `k` is a real constant The line `y=x` meets `y=k e^x` for `klt=0` at no point (b) one point two points (d) more than two points