You have recently overheard the following remarks:
(a) ‘When calculating variances, we ignore differences of volume of output, between original budget and actual, by flexing the budget. If there were a volume difference, it is water under the bridge by the time that the variances come to be calculated.’
(b) ‘It is very valuable to calculate variances because they will tell you what went wrong.’
(c) ‘All variances should be investigated to find their cause.’
(d) ‘Research evidence shows that the more demanding the target, the more motivated the manager.’
(e) ‘Most businesses do not have feedforward controls of any type, just feedback controls through budgets.’

Required:
Critically assess these remarks, explaining any technical terms.