The war poet Wilfred Owen was killed in action exactly one week before the war ended. The day after his death Owen was promoted to which rank?

The First World War began on 28th July 1914 and lasted for 4 years, 3 months and 2 weeks.  During that time almost 10 million servicemen and nearly 6 million civilians were killed and over 21 million were wounded.  Almost 2% of the world's population died as a direct result of this truly horrific conflict.