201. The piping that routes an oil cargo from the manifold directly to a cargo tank and serves only one tank is known as a __________.

A tank drop is a dedicated cargo line connecting the deck piping directly to a single cargo tank. This distinguishes it from branch lines, which serve multiple tanks, and filler lines, which are generic terms for tank loading. The question specifies a line serving only one tank, aligning with the definition of a tank drop.