Innovative designs manufacture wooden crates. Following is the cost related to company: $54,000 $350 $38,000 Wood used in crate production Nails (insignificant and variable expense) Direct labor Plant utilities: $1,500 each month, plus $0.40 for each kwh used each month Annual rent expense $21,400 Innovative designs use 500 kwh each month. Total manufacturing cost for the year under variable costing approach is: a. $94,750 b. $134,150 c. $94,400 d. $92,550