A is exhaustive, as exhaustion is a noun, which doesn't work here. For number 2, I fail to see the point of the question. All are possible, though I think "decent" most closely matches the meaning of honest, which is probably the point here. For number 3, attained is the ususal cliché for a rank, although to achieve a rank is not so wrong... the only difference between the two words is their French etymology... achieve tends to mean "reach and finish" while attain tends to mean "reach and hold". So the second and third questions involve what we might regard as splitting hairs, so if it is from a great big public exam... poor kids, they have a hard life.
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