how do we know which conformation is more stable? Please explain in detail.

Thank you!

1. (8marks) (i) On the answer sheet, complete the partial structures for the two chair conformations of cis-1bromo-4-sec-butylcyclohexane. (ii) On the answer sheet, complete the partial structures for the two chair conformations of trans1 - bromo-4-sec-butylcyclohexane. (iii) Designate which conformation (A or B ) is more stable in both part (i) and (ii). (circle one for each on the answer sheet). Explain your choice for each answer (maximum 10 words)