Illegal touching or what?

[gtwbam]

The play above is with 11 players. So assuming there were 11 players for A at the snap and its 3rd and 5 at A's 25 yard line. A1 takes the snap and throws a completed forward pass to A11 an ineligible receiver, at A's 40
yard line. A11 is then immediately tackled by B1 at A's 40 yard line.

1. Now there is definitely illegal touching, which is enforced at the spot of touching. However this would give A a 1st down from its own 35.

However; would B have the option to decline the illegal touching penalty in favor of an ineligible downfield penalty which would be assessed from the previous spot, which would give the ball to A on their own 20 and a replay of
3rd down.