Anthony purchased shirts and trousers in a ratio of \(4\) to \(5,\) where \(a\) is the number of shirts purchased and \(b\) is the number of trousers purchased. If Anthony buys more shirts and trousers, what is the new ratio of \(a\) to \(b?\)

1) Anthony only purchases shirts and trousers \(9\) at a time

2) \(a\) is increased by \(4x\) and \(b\) is increased by \(5x,\) where \(x\) is a positive integer

The OA is B