The safest and most appropriate method to determine if a base is stronger than an acid from the provided options is:
C. Use blue litmus paper.
Blue litmus paper is used to test pH: if an acid is present, the blue paper will turn red, indicating that the solution is acidic. This can help you identify the presence and relative strength of the acid compared to a base when using red litmus, which turns blue in the presence of a base. Options A, D, and E involve taste or feel, which are unsafe methods, while option B (using a conductivity apparatus) could provide some information about the strength of electrolytes but is more complex. Therefore, using litmus paper is the simplest and safest method to assess acidity and basicity.