Vector Sum for Equilibrium Steps:

• Identify that equilibrium requires the vector sum of all forces to be zero, meaning forces balance completely.
• Examine each diagram to see if the vectors form a closed polygon (head-to-tail addition returns to start).
• For options A, B, and C, note if the resultant is non-zero (unbalanced direction or magnitude).
• Confirm option D shows vectors closing perfectly, indicating zero net force.

Why D is correct:

• The vectors in D form a closed triangle, satisfying Newton's first law where ΣF = 0 for equilibrium.

Why the others are wrong:

• A: Vectors point in mostly the same direction, yielding a non-zero resultant.
• B: Unequal opposing forces create a net force away from balance.
• C: Vectors do not close, leaving an unbalanced component.

Final answer: D