Answer:
The statement that best expresses the theme of the poem is Young soldiers don't know what they're getting into when they sign up for war.
Step-by-step explanation:
The poem Boy Soldier by Fred D'Aguiar talks about the hard life that young soldiers have as they start to face the cruel reality of war and become responsible of many adult things that they are not ready to deal with yet, the poem follows the theme of these young soldiers having trouble to live this new kind of life they have.