What kind of caulking should I use in the following applications:

a. between a tub and a wall
b. on a roof
c. between 2 ceramic tiles
d. between base molding and a wall

What kind of caulking should I use in the following applications:

a. between a tub and a wallSilicone rubber sealer.
b. on a roofHenry's cold process for a quick tar fix. Spotting pop-ups use silicone rubber.
c. between 2 ceramic tiles Use grout first, then let it cure, then use clear silicone sealer rubbed into the grout.
d. between base molding and a wallUse a cheap DAP paintable latex and finger spread. nm

For Tile I Use A Grout Caulk. If Your Just Use Grout In The Corners It Will Crack. For Molding Just A Paintable White Silicone Caulk Is Fine. For Bathroom You Can Get A Mildew Resistant Caulk.
Hope This Helps , Nichols Trim And Carpentry