Keely filed her 2014 Form 1040 on April 4, 2015. What is the applicable statute of limitations in each of the following independent situations?
a. The taxpayer incurred a bad debt loss that she failed to claim.
b. A taxpayer inadvertently omitted a large amount of gross income.
c. Same as (b), except that the omission was deliberate.
d. A taxpayer innocently overstated her deductions by a large amount.
e. What if no return was filed by the taxpayer?