Read the excerpt from Team Moon. The trouble with option 2 was that the venting might push the fuel to an unstable condition. Or, another possible outcome of the “burping”: what if the landing gear hadn’t deployed correctly? Could any movement, or any resulting burst—no matter how small—tip the LM over? Many a voice in the debate thought the safest option was to abort—now! But that opinion was quickly overruled by the Grumman and NASA leadership (who were confident of the landing gear), and the consensus of the leaders was that it would be safe to gently, gently burp the engine.

Which detail from the excerpt identifies a solution?

the venting might push the fuel to an unstable condition
that opinion was quickly overruled by the Grumman
what if the landing gear hadn’t deployed correctly
it would be safe to gently, gently burp the engine