Among all the means of transport, ________ transport is cheapest and slowest for international business. A: sea B: rail C: road D: air

Given the following output：  A:  The speed of the slowest interface in the port channel B:  The combined speed of all interfaces configured in the port channel C:  The combined speed of all interfaces in the port channel that are up D:  The speed that can be achieved if all buffers are used

Tanya can swim faster than Jack but slower than Sally. Harry usually swims faster than Jack, sometimes swims faster than Tanya, but never swims faster than Sally. Who is the slowest swimmer A: Tanya. B: Sally. C: Harry. D: Jack.