Let $W(n)$ and $A(n)$ denote, respectively, the worst case and average case running time of an
algorithm executed on an input of size $n$.
Which of the following is always true?
(A) $A(n) = \Omega(W(n))$
(B) $A(n) = \Theta(W(n))$
(C) $A(n) = O(W(n))$
(D) $A(n) = o(W(n))$
What do all these options "mean"? I find it hard to reconcile the graphs exemplifying asymptotic notation and abstract situations such as this one.