When Congress placed the Transportation Security Administration $($TSA$)-$the agency in charge of airport security$-$in the Department of Homeland Security rather than the Department of Transportation, Congress

$$ a$)$ signaled that the Department of Transportation is a useless executive department.

$$ b$)$ signaled that domestic security concerns were to be a more central aspect of TSA's mission than facilitating transportation.

$$ c$)$ attempted to decrease the importance of airport security.

$$ d$)$ attempted to make the Department of Homeland Security less efficient than the Department of Transportation.