Starting at point A$,$ a change in tax laws that encouraged households to save more would likely cause the quantity of loanable funds traded to a$.$ decrease to $$80$ and the interest rate to fall to $4\%($point B$).$b$.$ increase to $$160$ and the interest rate to fall to $4\%($point D$).$c$.$ increase to $$160$ and the interest rate to rise to $7\%($point C$).$d$.$ decrease to $$80$ and the interest rate to rise to $7\%($point E$).$