When creating an overview visualization of a large dataset, it is most important to:

a) display only an important subset of the datapoints so as to not overwhelm the user

b)pack as many details as possible into the display to be as efficient and informative as possible

c)display all of the data using a simple representation and axes that spread the data out as much as possible

a) Display only an important subset of the datapoints so as to not overwhelm the user.

It's important to show only the information that the user needs or requested. The user won't care about other data displayed on the screen that doesn't have anything to do with the information requested.

Displaying more information or extra details that are not needed would only confuse the user and also slow the process. For example, imagine having this data:

Some datapoints from the list above could be omitted, depending on which information the user needs to consult. By doing an overview visualization, maybe the user would only like to see the employee's name, role and id.