To simplify a - {4b - [a - (5b - c) + 3c - (a - b - 9c)]} , we group the like terms and perform addition adn subtraction to these grouped terms. no multiplication nor division is applied. In thi case, the grouping results to
a - 4b + a - 5b +c + 3c - a + b + 9c = a -8 b + 13c. answer is B