In order for the idle/transfer slot circuit to start it needs air.

As an experiment, with the engine at idle, cover as many idle air bleeds with your fingers.

What happens?

Does the engine die because of lack of air?
lack of fuel?

The air bleed regardless of circuit,( idle/transfer slot, intermediate, or main well-booster) follows two rules.

smaller- circuit starts slower ie time delay if you will. once it starts it keeps getting richer.

larger- circuit starts quicker ie time delay is shorter. once it starts it tends to lean out.

all these things happen on some sort of a curve.

Air is needed to properly start the flow.

My anwser is B.

My on tuning range for idle/transfer slot circuit

ifr-.030" to .040"
iab- .050" to .070"

also a jet in the main body for the transfer slot works well
slot jet .070" -.104"