Answer:
C
Explanation:
2ab * sqrt[3](192ab^2) - 5 * sqrt[3](81 a^4b^5) =
= 2ab * sqrt[3](4^3 * 3 * a * b^2) - 5 * sqrt[3](3^3 * 3 * a^3 * a * b^3 * b^2)
= 2ab * 4 sqrt[3](3 * a * b^2) - 5 * 3 * a * b * sqrt[3](3 * a * b^2)
= 8ab * sqrt[3](3 * a * b^2) - 15ab * sqrt[3](3 * a * b^2)
= -7ab * sqrt[3](3ab^2)
Answer: C