Final answer:
The correct order of ranks within the coal series, from low to high, is bituminous/lignite/anthracite.
Step-by-step explanation:
The correct order of ranks within the coal series, from low to high, is bituminous/lignite/anthracite.
Bituminous coal is the most abundant form in the United States, while anthracite is the highest grade of coal and is primarily used for metallurgical refining. Lignite is the lowest grade of coal with the lowest carbon content.
Therefore, option b) bituminous/lignite/anthracite provides the correct order of ranks within the coal series.