Why does the data sheet for the 7476 only give a minimum value for the clock pulse width (both HIGH and LOW)?

Why does the data sheet for the 7476 only give a minimum value for the

1.	Why does the data sheet for the 7476 only give a minimum value for the clock pulse width (both HIGH and LOW)?
A.	nominal value
B.	best-case condition
C.	worst-case condition
Answer» D.