Correct option is A
Euler’s formula for buckling is applicable primarily for long, slender columns where buckling occurs well before the material yields. This is characterized by a high slenderness ratio (λ), typically above a certain threshold. In practice, Euler’s formula becomes less accurate as the slenderness ratio decreases because, at lower slenderness ratios (such as below 80 for mild steel), the column tends to fail by yielding rather than elastic buckling. In such cases, other approaches (like the Rankine-Gordon formula) are often used to predict column behavior more accurately.
