Arrange the following compounds in order of DECREASING boiling points (going from the highest to the lowest): n-butane
n-octane
2,2,3,3-tetramethyl-butane
2-butene​

b

d

a

c

Explanation:

More carbons in longest chain = higher BP

D has a BP of 0.8

A has a BP -0.5

C is the lowest because the more branched it is the lower BP

i'm assuming that it's c.) red bank..

the positions which points up in upward carbon and down in downward carbon are axial

and vice versa holds true for equatorial positions

so the correct answer with labelled diagram will be