A short object of length L is placed along the principal axis of a concave mirror slightly away from the focus of the mirror (u ≈ f). What will be the length of the image? (symbols carry their usual meanings)

Correct option is B

Correct answer is B
Calculation:
From the mirror formula:
1/f = 1/u + 1/v => v = fu/(u - f).
The magnification (M) is:
M = -v/u = -(fu/(u - f))/u = -f/(u - f).
The length of the image is given by:
Limage = |M| × L => Limage = (f/(u - f)) × L.
Now, simplifying further:
Limage = (f2/((u - f)2)) × L.