The saying "Beware the Greeks bearing gifts" means you should not accept gifts from your enemies countries should not give gifts while in battle a person should be careful when traveling in Greece
people from Greece give poor gifts​

d. new methods of assembly are introduced.

explanation:

this allows for the goods to be made on a larger scale. not faster because now it is shown to be made better, hence the greater productivity in the question. it is calling for something new to be introduced.