What is the applicable filing period under the statute of limitations in each of the following independent situations?
a. No return was filed by the taxpayer.
b. The taxpayer incurred a bad-debt loss that she failed to claim.
c. A taxpayer inadvertently omitted a large amount of gross income.
d. Same as item c, except that the omission was deliberate.
e. A taxpayer inadvertently overstated her deductions by a large amount.