To answer this question, we need to understand which bowler has achieved the best figures of 5-6 in T20 Internationals.
Option A) Anil Kumble - This option is incorrect because Anil Kumble was not a T20 International player. He mainly played Test and ODI cricket.
Option B) Umar Gul - This option is correct. Umar Gul, a former Pakistani cricketer, achieved the best figures of 5-6 in T20 Internationals. Gul accomplished this feat against New Zealand in the 2009 ICC World Twenty20 tournament.
Option C) Nathan Bracken - This option is incorrect. Nathan Bracken is an Australian cricketer who primarily played in ODI and Test cricket. He did not achieve the best figures of 5-6 in T20 Internationals.
Option D) Lasith Malinga - This option is incorrect. Lasith Malinga, a Sri Lankan cricketer, holds numerous records in T20 Internationals, including the most number of hat-tricks. However, he did not achieve the best figures of 5-6 in T20 Internationals.
The correct answer is B) Umar Gul. He achieved the best figures of 5-6 in T20 Internationals.