The correct answer is A. A 1901 opinion piece about building the canal, form the New York Times online archive.
Step-by-step explanation
When we carry out an investigation it is necessary to argue our position using valid, reliable, and original sources as support that allows us to know in depth the subject we are talking about. In general, primary sources are produced by individuals or institutions that have lived during an event, they allow us to get an idea of what a situation was like at a certain moment or to know the point of view of someone involved in an event in the past, by what can be considered as primary sources photographs, newspapers, chronicles, among others.
Additionally, primary sources can also be specialized academic documents such as a doctoral thesis, a master's thesis, a book, patents, as well as other supports.
According to the above, if you are searching the reasons for the building of the Panama Canal in the late nineteenth century the most adequated source is A 1901 opinion piece about building the canal, form the New York Times online archive because it is a source that allows the reader to know the opinion of a person of that time on that fact without any interpretation of another person. According to the above, the correct answer is A.