According to Jones (1991), a) Firms manipulated reported earnings downwards using positive discretionary accruals when ITC reviewed their cases b) Firms manipulated reported earnings downwards using negative discretionary accruals when ITC reviewed their cases c) Firms manipulated reported earnings upwards using positive discretionary accruals when ITC reviewed their cases d) Firms manipulated reported earnings upwards using negative discretionary accruals when ITC reviewed their cases