Question

what is the primary purpose of this poster?
○ to express the importance of the alliance between the united states and britain
○ to encourage people to join the armed forces
○ to convince people to support the arts during wartime
○ to celebrate the victory at the end of the war
image: poster with text \side by side - britannia!\ and \britains day dec.7th 1918 mass meeting\, showing figures (uncle sam - like, britannia - like, lion, eagle)

Explanation:

The poster shows Uncle Sam (representing the US) and a figure with British symbols (Britannia, Union Jack shield, lion) side by side. The title "SIDE BY SIDE - BRITANNIA!" and the context of 1918 (near WWI's end) suggest emphasizing the US - UK alliance. Other options: joining armed forces isn't shown, arts support is irrelevant, and victory celebration is unlikely as Dec 7, 1918 is before WWI's official end (Nov 11, 1918? Wait, maybe a typo, but the imagery is about alliance, not victory yet or recruiting/arts).

Answer:

to express the importance of the alliance between the United States and Britain