Which of these was Germany permitted to keep under the terms of the Treaty of Versailles: a standing army, new military weapons, monetary reparations to cities, or rights to all territories?

What the question is really testing

This is asking what the Treaty of Versailles (1919) allowed Germany to have after World War I. The treaty reduced Germany’s military power and territory, so the correct choice will be something allowed in a limited form.

Checking each option against the treaty

• A standing army: Allowed, but capped at $100{,}000$ soldiers and no conscription.
• New military weapons: Not allowed, Germany was restricted from having or developing many modern weapons (for example tanks and military aircraft).
• Monetary reparations to cities: Wrong direction. Germany had to pay reparations to the Allies.
• Rights to all territories: Not allowed, Germany lost territory (for example Alsace-Lorraine returned to France).

Correct choice

A standing army is the only option Germany was permitted to keep, even though it was tightly limited.