Sherrington inferred the presence of a gap between neurons based on . a. the existence of spinal reflexes b. slower than predicted speed of conduction c. suppression of reflexes d. inconsistent occurrence of conduction

The correct answer is letter b. It is because Sherrington has inferred that the gap between the neurons are present base on the predicted speed of conduction in which should be slower, and by that, the correct answer is letter b as it reads that they should be base slower than the predicted speed of conduction.