Of the choices given here, A is the best answer.
Both B and D are unlikely to actually happen. There is no reason why the cost of pollution permits would not be passed on to consumers. Similarly, voters who would be angry about the level of taxation on businesses would be just as angry about costs imposed on businesses through pollution permits, which are really just a form of tax. As for C, we have no way of knowing without knowing the price of the pollution permits or the level of the tax.
A is the best answer because pollution permits would be subject to market forces of supply and demand. Those forces would determine the right price for the permits. By contrast, with the tax, the government would have to try to guess on the demand curve and the optimal tax rate. This is very hard to do.