In the context of fluid dynamics, interference refers to
a) the results of two waves meeting
b) anything that changes the course of a wave
c) the consequences of waves hitting the shore
d) the effect of different mediums of waves interacting

Where is the graph ?

Ch4 and ph3 are both covalent since they are composed both of non-metals.    ch4 is non- polar because of  london forces and has a geometry of tetrahedral  ph3 , on the other hand, is umbrella shaped polar and has dipole-dipole intermolecular force (imf) . since ph3 is polar, it has a stronger imf