What is the difference between executive order and a law? which one is stronger and why?

The EO only gives authority within the executive branch and those federal agencies. The EO doesn't have the legal weight of a law of the land. It can be rescinded by both the president and/or Congress when they provide oversight. A law of the land requires a vote by Congress to be rescinded

EXECUTIVE ORDER or EO are exclusively prerogative of the president that do not need the promulgation of congress. The president can issue EO left and right, without the approval of congress because it is exclusively intended for executive branch of the government and not the legislative body like congress. While a law are passed inside the congress for their deliverance and approval.

b). (sounds as the best answer)

discovery of cape town-portuguese empire

development of africans language-dutch east india company

introduction of railway-british empire