Option a is correct as international trade requires efficient allocation of resources, by avoiding wastages and unnecessary costs, which increases profits.
Option b is correct as international trade increases the income of the people engaged in trade and the economy. Thus, it leads to a higher standard of living.
Option c iscorrect as international trade helps countries gain greater consumer and producer surplus by engaging in specialization. There isno wastage of resources;an efficient outcome is obtained.
Option d is correct as it promotes competition. The producer has to stay in the market with rising players. They must develop new technology or differentiated products so that their products are used extensively.