I have distributed and analyzed a survey regarding teaching quality. For some of the questions, I ask how often a given teaching method is used. When doing this I ask them to select one of the following options in a question such as this example below:

My professor used class participation/discussions in...
a) 0% - 25% of classes
b) 26% - 50% of classes
c) 51% - 75% of classes
d) 76% - 100% of classes

When analyzing this data I would like to use a single value for a measure of central tendency to compare the different methods and even visualize them in a barplot. When doing this could I use the mean value for each teaching method or is the median the more statistically appropriate measure to use. The problem I have come up with when using the mean and visualizing the information in a barplot is that I do not know what I would say if someone asked me what the value of one of the bars are, given that they are in between the options. Furthermore, how would I elaborate if someone asked what the numerical difference is between two bars that are placed in between options? Thanks for anyone willing to help.