Mcq

The audit manager has asked you to review results of some statistical sampling testing which resulted in 20% of payables balance being tested
Testing results indicate that there is a $45000 error in sample, $20000 which is due to invoices not being recorded in correct period as a result of weak controls and additionally there is one of error of $25000 which was made by temporary clerk. Materiality is set at $50000
What would be an appropriate course of action on basis of these results
a) The error is immaterial and therefore no further work is required
b)The effect of control error should be projected across the whole population
c)Poppy co should be asked to adjust the payables fig by $45000
d)A different sample should be selected as these results are not reflective of the population

Sir correct ans is B but please can you explain