What is the relationship between the members of following pairs of structures?

What is the relationship between the members of following pairs of structures? Are they structural or geometrical isomers or resonance contributors?

(i) Structural isomers (differ in position of the functional group)
(ii) Geometrical isomers (trans and cis isomers respectively)
(iii) Resonance contributors (differ in the position of electrons but not atoms.)