【单选题】The most sparsely populated county in Wales is where you will find Britain's happiest place, say researchers, as Powys tops the list of 273 districts, with Edinburgh apparently the most miserable plac...
A.
The number of households surveyed is not very large.
B.
The survey was not carried out by the research team.
C.
There is no sample from the districts of Ireland.
D.
The findings are interesting but not academically useful.