The answer is the first one.
Answer:
A. To identity high- and low-pressure systems
Explanation:
Isobars are similar to the level lines on a topographic map, showing areas of similar pressure, they are also drawn in circles to represent the areas of similar air pressure over a geographical map.
Isotherms are usually displayed in color showing areas over a map that have the same temperature or are covered by a similar temperature system (heat or cold front for example).
Both are used in electronic media mostly (although in print in newspapers too), over a geographic map to position the systems.
I believe the answer is D. don't take my word for it though I may be wrong
