You must have studied in your school physics that when several components are connected in parallel across two points, the voltage drop is same for all of them. Why this is so ? Well we explain it from another point you must have read.
Electric field is a conservative field just like gravitational field i.e work done in electric field is also independent of path as it happens in gravitational field. Thus the change of path doesn’t increase or decrease the work. Hence if we were to move from point 1 to 2, we have 3 different paths available namely A.B & C. If you go via 1-A-2, 1-B-2, 1-C-2, it wont matter because you would end up doing same amount of work be the lengths of path of any amount. Since potential is basically the work done in moving unit charge between two points, hence same work done means same potential.
Hope this simple and short explanation is helpful !