Why (B) is correct:
"(B) takes for granted that the largest tomb found so far must be the largest that was built."
Just because this is the largest tomb found doesn’t mean it’s the largest that ever existed.
There could be larger undiscovered tombs, or Alexander's tomb might have been destroyed, hidden, or built elsewhere.
The argument wrongly assumes that finding the biggest tomb means it's Alexander's, which is flawed reasoning.
Why the other choices are wrong:
(A) takes for granted that greatness can be attained only by military conquest → Wrong
The argument doesn’t make a general claim about greatness. It only assumes a connection between Alexander’s greatness and the size of his tomb.
(C) does not show how the recently discovered tomb compares with other tombs from the same period that have been found in other regions → Wrong
While this might be relevant for historical analysis, the flaw in the argument is about assuming the largest tomb found so far is Alexander’s, not about regional comparisons.
(D) fails to evaluate the significance of the fact that Alexander’s empire did not survive his death → Wrong
The argument is about who is buried in the tomb, not about the fate of Alexander’s empire. This fact doesn’t weaken or strengthen the conclusion.
(E) takes for granted that archaeologists can determine the size of the tomb from its remains → Wrong
The argument assumes the tomb is the largest, but it’s not questioning whether archaeologists can measure it. That’s not the key flaw here.