Isobars are similar to height lines on a geographical map, and they are drawn so that they can never cross each other. Meteorologists use isobars on weather maps to depict atmospheric pressure changes over an area and to make predictions concerning wind flow.
Aluminium has the least resistance since It has 3 free electrons per atom. Its resistivity is low compared to other metals provided in the choices (gold, nichrome, tungsten). Low resistivity of metals means a high conductance of the metal referred to.