22. Greg's cost formula for its lawning cost is $1,800 per month plus $400 per each spring day. In April, they planned for lawning services of 14 spring days, but the actual level of lawning services was 20. The actual lawning cost for the month was $8,000. The activity variance for the lawning cost in April should be: a) $2,400 U b) $1,050 F c) $950 F d) $2,400 F