A position obtained by crossing lines of position taken at different times and advanced to a common time is a(n) （）.

A.fix
B.dead-reckoning position
C.running fix
D.probable position

A.plane tangent at one point
B.cylinder tangent at one parallel
C.cone tangent at one parallel
D.series of cones tangent at selected parallels

A.when at anchor
B.only when making way
C.at any time when underway
D.only when the identifying lights are not being shown