In my Form 1095-A, Row B & C in Part III are all blank. Turbotax says to leave this blank, but I see "Please enter an amount" under each of the boxes I left blank. Help?

You should leave the boxes blank. 

The reminder "Please enter an amount" applies only when there is a non-zero amount in the box.

Unfortunately, the form won't let you leave values blank -- unless you leave the entire row blank. 

On my form, only column A has values, column B and C are blank. Leaving these blank in Turbotax and trying to submit generates red error text under each of the boxes I left blank. 

I did find a solution though. You can find out the Row B value at https://www.healthcare.gov/tax-tool/#/. If you're in a state or locale (like DC) that has it own program, you can google something like "slcsp lookup tool" and your state. I guess most don't get the monthly advance payment for Row C, so I entered 0 for that column.

This is a fix that Turbotax needs to address given that there is no way to submit the form with blank values.