Yummy Treats Bakery (YTB) makes pastries and muffins. YTB gathered the following information for the current year regarding its use of flour and butter (flour is a direct material for pastries and butter is a direct material for muffins): rials) Actual quantity purchased and used per batch (pounds)? \\( 4.5 \\mathrm{lbs} \\). How much is the efficiency variance for butter? \\( \\$ 5,100 \\mathrm{U} \\) \\( \\$ 2,400 \\mathrm{~F} \\) Actual quantity purchased and used per batch (pounds)? How much is the efficiency variance for butter? \\( \\$ 5,100 \\mathrm{U} \\) \\( \\$ 2,400 \\mathrm{~F} \\) \\( \\$ 2,400 \\mathrm{U} \\) \\( \\$ 5,100 \\mathrm{~F} \\)