Consider the IRR and ERR measures of worth. If we define a root to mean a value for the measure that results in \(\mathrm{PW}=0\), then which of the following statements is true?

a. Both IRR and ERR can have multiple roots.

b. IRR has only a single root, but ERR can have multiple roots.

c. ERR has only a single root, but IRR can have multiple roots.

d. Both IRR and ERR have only a single root.