What is the radius of channel, when electrical breakdown occur?

• A. 4 ¬¨¬®¬¨¬µm
• B. 6 ¬¨¬®¬¨¬µm
• C. 8 ¬¨¬®¬¨¬µm
• D. 10 ¬¨¬®¬¨¬µm