How do electric field lines indicate the strength of the field? by how long the lines are by how close the lines are by the direction the lines are pointing by showing the charge that creates the lines

Electric field strength is a vector quantity; it has both magnitude and direction. The magnitude of the electric field strength is defined in terms of how it is measured. If an electric charge can be denoted by the symbol q.  This electric charge will create an electric field, then this charge is named source of charge. The strength of the source charge's electric field could be measured by any other charge placed somewhere in its surroundings. The charge that is used to measure the electric field strength is referred to as a test charge since it is used to test the field strength. So, the conclusion is:

By showing the charge that creates the lines.

The answer is by how close the lines are. I took the test and got it right.