When in command of a lifeboat under oars，the command TOSS OARS means to（）.
A.lift oars to vertical position，trim blades fore and aft with handles resting on the thwarts
B.complete the stroke，come to Oars，raise the oars smartly to the vertical，rest handles on footings and trim blades fore and aft
C.place oars in row locks directly from the boated position or from Stand by oars position
D.complete the stroke (when rowing in ahead motion)，raise the oars with crook of elbow to about 30 degrees，swing blades forward