Area moment of intertia of a t-bar

[NoobeAtPhysics]

Homework Statement

The area moment of inertia about the dashed axis is what?

Homework Equations

Paralell Axis theorem

The Attempt at a Solution

(1/12)bh³ + (1/12)hb³ + bh(h/2 + b/2)²

I don't understand how I am wrong

 

[haruspex]

(1/12)bh³ + (1/12)hb³ + bh(h/2 + b/2)²

Looks right to me, though you could collect up some similar terms. What is the official answer?