In 1942, the allies began their “europe-first” strategy by invading
the soviet union.
france.
japan.
north africa.

The answer is "North Africa."

Explanation:

North Africa was important because its control guaranteed access to the Mediterrenean Sea and it was necessary for launching an invasion of Europe. Following this logic, after having won control of northern African shores, the Allies  invaded Sicily and then the Italic peninsula itself.

what are the options?