HSK C7-9/V7-9
Correct

坛

/ tán / 
Strokes

Definition

platform/rostrum/altar

Example

As a Noun
altar (for sacrificial purposes, etc)
As a Noun
raised plot of land for planting flowers, etc
As a Noun
circles; world; arena
As a Noun
forum; platform
As a Noun
organization set up by a secret society to worship gods in a rally