Identify the type of IRA (Roth or traditional) that would be best for a taxpayer in each

Question:

Identify the type of IRA (Roth or traditional) that would be best for a taxpayer in each of the following circumstances:
a. Sharon believes she will be in a higher tax bracket when she withdraws the money in retirement.
b. Ken believes he will be in the same or a lower lax bracket in retirement.
c. Susan wants to use her retirement savings for building her estate to pass on to her children.