Step 1: Think about what Khali means:
Khali means empty. Without a clap, the matching mark should look empty. A zero looks like an empty circle.
Step 2: Link the shape to the meaning:
Bhatkhande used 0 for the empty beat Khali, X for the first beat Sam, and numbers for the clapped beats.
Step 3: Remove wrong symbols:
X is taken by Sam. The numeral 1 is a clap count. The plus sign belongs to another system. So these three do not stand for Khali.
Step 4: Conclude:
The only symbol left is 0, which is option 2. This is the mark you see on the empty beats of taals like Teentaal.
Step 5: Recheck every option once more:
Option 1: +. This is not the answer.
Option 2: 0. This is the correct choice.
Option 3: 1. This is not the answer.
Option 4: X. This is not the answer.
Final Answer:
Khali is shown by 0, option 2. \[\boxed{2}\]