During which conflict was Wilfred Owen a poet and soldier?

Wilfred Owen was a poet and soldier during World War I, which significantly influenced his writing and poetic themes. His experiences in the trenches and the harsh realities of war shaped his perspective, leading him to create powerful and vivid poetry that conveyed the horrors of combat, the suffering of soldiers, and the futility of war. Owen's works, such as "Dulce et Decorum Est" and "Anthem for Doomed Youth," reflect his deep compassion for fellow soldiers and a strong anti-war sentiment, solidifying his legacy as one of the most important voices of war poetry in the English language.

The other conflicts mentioned do not correspond with Owen's life or literary contributions. World War II occurred after Owen's death in 1918, and the Korean War and Vietnam War came much later and do not relate to Owen's context as a poet or soldier. His significance lies in his role during World War I, making it the correct answer.