Which of the following is true for normal projects if the cost of capital is positive?
a) If a project's IRR is positive, then its NPV will always be positive
b) If a project's NPV is negative, then its Modified IRR will be negative
c) If a project's NPV is positive, then its Profitability Index will always be positive
d) If a project's IRR is positive, then its Discounted Payback Period will exist