Correct option is D
Explanation-
Fast axonal transport in neurons refers to the rapid movement of organelles, synaptic vesicle precursors, and proteins along microtubules with the help of motor proteins like kinesin (anterograde) and dynein (retrograde). In humans, fast axonal transport moves at approximately 200–400 mm/day. Given the distance from the spinal cord to the foot (which can be over 1 meter in tall individuals), even at this high rate, it takes approximately 2–3 days for synaptic vesicles to travel this entire distance.
Incorrect Options-
Option a (5–10 seconds): Unrealistically fast — not possible over such long axonal distances.
Option b (10–15 minutes): Still too fast — would require speeds far beyond known biological limits.
Option c (5–6 hours): Faster than realistic for 1-meter travel at known rates.
Final Answer:
Option d – 2–3 days is correct
