I think the answer is A) stratified random sampling! Stratified random sampling is when sunsets of individuals are created based on similar criteria, which sounds the closest to the problem because stratified can split a group and does not have to be fully equal.
Non random sampling doesn’t fit because it’s clearly stated that it’s random.
Systematic random sampling is based on intervals in a group.
The next closest answer would be simple random, which is when a subset of individuals are chosen from a larger group with all having the same probability.
the original price is "x", or 100%.
but we know that if we reduce "x" by 20%, namely 100% - 20% = 80%, the 80% of "x" is really £50, what is "x" or the 100% anyway?

Answer:
627 pounds
Step-by-step explanation:
It would most likely be D theory