The US government is deeply in debt. If its foreign lenders begin to doubt its ability to pay them back, the demand for credit in the US will increase $($rightward shift of the credit demand curve$).$

the supply of credit in the US will decrease $($leftward shift of the credit supply curve$).$

the equilibrium interest rate in the US will rise.

$($b$)$ and $($c$)$ above

$$longrightarrow

$$ Moving to the next question prevents changes to this answer.