If in a pin-jointed plane frame (m + r) > 2j, then the frame is
(Where ‘m’ is number of members, ‘r’ is reaction components and ‘j’ is number of joints)
A. Stable and statically determinate
B. Stable and statically indeterminate
C. Unstable
D. None of the above
Answer: Option B

If value is negative - structure unstable