Suppose the Official Rate of Unemployment Reported by Statistics Canada

Suppose the official rate of unemployment reported by Statistics Canada declines from one month to the next from 7.5% to 7.2%,but we also know that the stock of unemployed workers has not changed.How is this possible?

A) The labour force has declined due to out-migration of working-age people.
B) The labour force has grown as previously discouraged workers re-start their job-search process as unemployed individuals.
C) Some individuals who were previously outside the labour force have joined the labour force and immediately found jobs.
D) We have gone from a month with high seasonal unemployment to a month with low seasonal unemployment.
E) We have gone from a month with low seasonal unemployment to a month with high seasonal unemployment.