Which pair of molecules has the strongest dipole-dipole interactions?
ch4 and ch4 nh3 and ch4 co2 and ch4 nh3 and nh3 co2 and co2

NH3 and NH3

Explanation:

If hydrogen is bonded to a highly electronegative element, a strong dipole-dipole attraction is set up with strength ten times greater than normal dipole-dipole attractions, and it is crystal clear that electronegativity increase from left to right across the period and it decreases down the group. Nitrogen being electronegative more than Oxygen will exhibit a greater dipole-dipole attraction. As such, NH3 and NH3 is  the right answer.

heat or electricity in the atmosphere- c.

it's c (engineer's do their work with mechanical stuff not on any living being)