One of the obstacles to achieving one objective of ECOWAS is

Explanation

The question is asking about one of the obstacles to achieving one of ECOWAS's objectives. The options given are lack of common currency, colonial linkages, sovereignty of states, and language differences.

The correct answer is option A: Lack of common currency. This means that one of the challenges faced by ECOWAS in achieving its objective is that the member countries do not have a common currency. Currently, each country in ECOWAS has its own currency, such as the Nigerian Naira or the Ghanaian Cedi.

Having a common currency would make it easier for the member countries to trade and do business with each other. It would also help to promote economic stability and integration within the region. However, establishing a common currency is a complex process that requires coordination and agreement among the member countries.

While the other options listed in the question, such as colonial linkages, sovereignty of states, and language differences, may also present challenges to ECOWAS's objectives, the lack of a common currency is specifically mentioned as one of the obstacles.

In summary, the obstacle to achieving one of ECOWAS's objectives mentioned in the question is the lack of a common currency among the member countries. This means that each country has its own currency, which can make it more difficult to promote economic integration and cooperation within the region.

Note: The answer provided is based on the information given in the question. However, it is important to note that there may be other obstacles or challenges faced by ECOWAS in achieving its objectives that are not mentioned in the question. To learn more about this, please read the relevant sections of the recommended textbooks.