A rigid-jointed plane frame is stable and statically determinate if (where m is number of members, r is reaction components and j is number of joints)
A rigid jointed plane frame is stable and statically determinate if
A. (m + r) = 2j
B. (m + r) = 3j
C. (3m + r) = 3j
D. (m + 3r) = 3j