Multi-line graphs should be limited toSelect one:a.five–six lines.b.six–seven lines.c.three–four lines.d.two–three lines.

To answer this question, let's consider the readability and clarity of multi-line graphs:

a. Five–six lines.

• While it's possible to have five to six lines on a graph, it may start to become difficult to distinguish between the different lines, especially if they are close together or overlapping.

b. Six–seven lines.

• This many lines on a graph can make it very cluttered and confusing to read. It would be challenging to distinguish between the different lines and accurately interpret the data.

c. Three–four lines.

• This is a reasonable number of lines for a graph. It allows for comparison between different data sets, but is not so many that it becomes overwhelming or confusing.

d. Two–three lines.

• This is also a reasonable number of lines for a graph. It allows for clear comparison between two or three different data sets.

Therefore, the correct answer is likely either c. three–four lines or d. two–three lines. These options strike a balance between allowing for comparison of multiple data sets and maintaining readability and clarity. However, the exact answer may depend on the specific guidelines or preferences of your course or field.