GST stands for Goods and Services Tax.
It is an indirect tax, meaning it is levied on the supply of goods and services, and the final consumer bears the burden, not the person who pays it to the government (like a shopkeeper). This rules out options (A) and (D).
The primary purpose of the introduction of GST in India was to reform the country's indirect tax structure.
Before GST, there were many different indirect taxes levied by both the central and state governments, such as Central Excise Duty, Service Tax, VAT (Value Added Tax), Entry Tax, etc.
GST subsumed most of these taxes into a single, comprehensive tax structure.
Therefore, GST is a single tax that replaced multiple indirect taxes. This matches option (B).