A mass spectrum has two peaks at 78 and 80 m/z with approximately a 3:1 ratio. Another set of peaks at 63 and 65 m/z is also observed with a 3:1 ratio. The largest peak has a molecular weight of 43. The last noted peak is at 27 m/z. Which structure best fits the MS data

You know how the first one if filled up like the objects do the same but with the other categories

For cyclohexane compounds drawn in a chair conformation:   -axial bonds are vertical  -equatorial bonds are parallel to two bonds within the ring.  thus, as i assume the chair conformation is drawn:   -the x group is in an axial position, as are the five other vertical bonds.  -three axial bonds are on the top face of the ring  -the other three axial bonds are on the bottom face  the position of the second substituent on each ring carbon is equatorial.  gauche groups must be on an adjacent carbon such as carbon 6 and carbon 2, and also gauche groups are rotated by 60 degrees relative to each other.  drawing the newman projections for c1–c2 and c1–c6 aids in visualizing the groups that are gauche to the y group on c1.  click this link and watch some academic videos that may you more understand the topic