The current US Treasury yield curve is characterized by $\_\_\_\_\_\_\_\_\_\_.$

$($a$)$ a normal curve with a large spread between short$-$ and long$-$term bonds

$($b$)$ an inverted U$-$shaped curve with about a $1/2\%$ positive spread between short$-$ and long$-$term bonds

$($c$)$ a flat curve with long$-$term bonds slightly higher than short$-$term bills

$($d$)$ a normal curve with a small positive spread of the $10-$year over the $2-$year Treasury

$($e$)$ none of the above