The diameter of a cylinder is measured using vernier calipers with no zero error. It is found that the zero of the vernier scale lies between 5.10 cm and 5.15 cm of the main scale. The vernier scale has 50 divisions equivalent to 2.45 cm. The 24th division of the vernier scale exactly coincides with one of the main scale divisions. The diameter of the cylinder is:

Main scale can measure 5.10 and 5.15
∴Main scale division (s) = 0.05 cm
Least count (LC) =
(2.45 cm / 50 divisions) = 0.049 cm
The zero of the vernier scale lies between 5.10 cm and 5.15 cm of the main scale.
24th division of the vernier scale exactly coincides with one of the main scale divisions.
Reading = Main scale reading + (Vernier scale division × LC)
Reading = 5.10 cm + (24 × 0.049 cm) = 5.10 cm + 1.176 cm = 5.276 cm
The question has an error. The given options are not correct based on the calculations.
Let's assume the main scale reading is 5.10 cm
Reading = 5.10 cm + (24 × 0.049) cm = 5.10 cm + 1.176 cm = 6.276 cm
If the main scale reading is 5.15 cm
Reading = 5.15 cm + (24 × 0.049) cm = 5.15 cm + 1.176 cm = 6.326 cm
None of the options match these readings. There's a discrepancy in the question or the provided options.