When Projecting Future US Healthcare Spending as a Share of GDP

When projecting future US healthcare spending as a share of GDP into the long-run, it is likely that

A) it will take the shape of a U-curve.
B) it will take the shape of an inverted U-curve.
C) it will take the shape of a S-curve.
D) its positive slope with be becoming steeper over time.
E) there will be no stable pattern in its shape because of the upcoming reforms and uncertainty associated with them.