To determine the correct shear force diagram (SFD) and bending moment diagram (BMD) for a cantilever beam subjected to a point load P and a moment M, we can analyze the loading conditions step-by-step.

Step 1: Understanding the Load Conditions

• The cantilever beam has a fixed support at one end and is free at the other.
• A point load P is applied at the free end.
• A moment M is also applied at the free end.

Step 2: Analyzing the Shear Force

• At the free end, the shear force is -P (negative because it acts downwards).
• The shear force remains constant along the length of the beam up to the fixed support.
• At the fixed support, the shear force is also -P.

This results in a horizontal line in the SFD at -P.

Step 3: Analyzing the Bending Moment

• At the free end with the moment M, the bending moment starts as M.
• As we move towards the fixed end, the bending moment changes linearly due to the shear force -P.
• The equation for bending moment at a distance x from the free end: M(x) = M - Px.
• At the fixed end (x = L), the bending moment is: M - PL.

This results in a linear line in the BMD starting from M at the free end and reducing to M - PL at the fixed end.

Conclusion

The correct representation of the SFD and BMD follows these analyses.

The diagram shown above correctly reflects the constant shear force at -P and the linear variation of the bending moment.