Which of the following types of failures occur in the beam-column connections?1. Failure by lateral-torsional buckling2. Failure by combined instability in both the principal directions3. Failure by combined twisting and bending on the torsionally weak sections4. Failure by combined twisting and bending when plane of bending does not contain the shear centre

• A. 1, 2 and 3 only
• B. 1, 3 and 4 only
• C. 1, 2 and 4 only
• D. 2, 3 and 4 only