Help regarding trees in discrete mathematics

[danieljames21]

Write down the vertex sequence for the pre-order, in-order and post-order traversal of the tree below.

My lecturer has not touched on this subtopic for trees (transversal) however she posted this question to warm us up when she teaches on Monday. After my own studying, The answer for pre-order should be: a,b,e,f,l,m,n,c,g,h,o,p,d,i,j,q,s,t,u,r,k.
My question for this is is my answer correct? or am I approaching the question in a completely different matter. If so, could you please show me how a question like this is solved?

 

[Dr.Peterson]

It looks correct to me. It's just a matter of following the definition, whether from your textbook or another reliable source.

Why are you unsure?