F35 A, B and C

By any chance, could anyone describe what the cost is of the F-35 B in terms of “diminished capacity” when compared to the A and C version (in other words, what does the STOVL capability cost in terms of operationnal capacity)? A complementary point would be to determine whether the “diminished capacity” is broadly similar to previous STOVL aircraft, or whether is has been reduced (insofar as this can be determined)???