Find the Test Statistic $\chi ^ { 2 }$ By McNemar's Test

Multiple Choice

Find the test statistic $\chi ^ { 2 }$ by McNemar's test.
-categorical data: a =25, b = 15, c = 20, d = 10

A) 5.600
B) 2.314
C) 0.457
D) 1.029