The correct option is A 36
Bipartite graph {u, v} where u and v are partition on vertices:
(a) {1,11}⇒1×11=11 edges maximum
(b) {2,10}⇒2×10=20 edges maximum
(c) {3,9}⇒3×9=27 edges maximum
(d) {4,8}⇒4×8=32 edges maximum
(e) {5,7}⇒5×7=35 edges maximum
(f) {6,6}⇒6×6=36 edges maximum
∴ Maximum number of edges in a bipartite graph on 12 vertices = 36 edges.