What is the mean spreading rate of the oceanic crust, ( s )? This is the amount of spreading per year required to generate oceanic crust at the rate determined in the problem.
a) ( s = 1.5 ) cm/year
b) ( s = 2.0 ) cm/year
c) ( s = 2.5 ) cm/year
d) ( s = 3.0 ) cm/year