$($Related to Checkpoint $11\mathrm{.}1$ and Checkpoint $11\mathrm{.}4)($IRR and NPV calculation$)$ The cash flows for three independent projects are found below:

a$.$ Calculate the IRR for each of the projects.

b$.$ If the discount rate for all three projects is $20$ percent, which project or projects would you want to undertake?

c$.$ What is the net present value of each of the projects where the appropriate discount rate is $20$ percent?

a$.$ The IRR of Project $A$ is

$\%.($Round to two decimals$)$