Step 1: The point being tested is the spacing rule for two live vaccines that are not co-administered.
Step 2: Live vaccines may be given simultaneously, but if missed, the immune response stirred up by the first live vaccine can interfere with the take of a second one given soon after.
Step 3: To prevent this blunting, guidelines require a minimum separation of four weeks between the two injected live vaccines.
Step 4: So the shorter 2-week gap is inadequate and the recommended interval is 4 weeks.
\[\boxed{4\ \text{weeks}}\]