XX produces several models of clocks. xx has provided the following unit costs for its commercial clocks: Direct matenals $100 Direct labor 140 Variable overhead 80 Fixed overhead (100% unavoidable) 150 XX needs 1,000 clocks annually. An outside supplier has offered XX to produce clocks for $380 each. Required: The calculation of total relevant costs of make vs buy will show: $20,000 difference in cost in favour of buying $90,000 difference in cost in favour of buying $60,000 difference in cost in favour of making correct answer is not provided