Question

What does it mean that Birnam wood comes to Dunsinane?

It's a meaningless riddle meant only to confuse.

Macbeth's banquet hall in Dunsinane is made from trees from the Birnam forest

The advancing army rides to Dunsinane holding branches from Birnam wood.

Macbeth's body will be buried in Dunsinane in a casket made from the trees of
the Birnam forest.

Answer 1

C) The advancing army rides to Dunsinane holding branches from

Step-by-step explanation:

The third prophecy shows that Birnam Woods must be brought to Dunsinane in order for Macbeth to be defeated. Malcolm gives the order to have trees chopped down and their branches held in front of the army troops. This will make it seem like the Birnam Woods are advancing on them as they go to Macbeth's castle.

When Macduff kills Macbeth in combat, the ultimate prophecy has been fulfilled.

Photo below:

The Birnam Oak is the only tree to survive from Shakespeare’s time CREDIT: David Cairns/Alamy