Alternative locations for an advanced wastewater recycling plant are being evaluated using four attributes identified as attributes 1, 2, 3, and 4 with weights of 0.4, 0.3, 0.2, and 0.1, respectively. If the value rating scale is from 1 to 10, and the ratings are 3, 7, 2, and 10 for attributes 1, 2, 3, and 4, respectively, the weighted attribute measure R is closest to:

(a) 3.7 (b) 3.9 (c) 4.0 (d) 4.7