W E Inject a Slightly Depolarizing Current into an Axon

W e inject a slightly depolarizing current into an axon at x = 0 cm continuously monitor the potential at x = 5 cm away. At steady state, the resting membrane potential is -70 mV. At the point of injection,the potential is -60 m V and at x = 5 cm away it is -66.3 mV. W hat is the space constant?

A) 2.5 cm
B) 5.0 cm
C) 10.0 cm
D) 15.0 cm
E) 20.0 cm