Drop a set of Cluster Mines

[脸黑的饿货]

I've played against a tri-Firespray-class squad and met a scene in the recent tournament play (although the key part of it did not actually happen), and is keen on how to resolve the game. 

Here is the scene -

A Firespray-class flies along an edge of the play area and dropps a set of Cluster Mines, and part of 1 of the side mine is outside the play area. How should it be resolved?

a) The charge of the upgrade is spent, the one that is partially outside the edge should be removed while the rest 2 are safe and stay, because each of the Cluster Mines is an individual device;

b) The whole set should be returned to the supply and the charge spent should be recovered as the drop does not occur, because the 3 Cluster Mines share the same upgrade charge.

Which way is right?

[Kris M]

A device cannot be placed so that a portion of the device would be outside the play area. If this would happen, play is reversed to before the device was placed—the device is not placed, any charges spent and other costs paid are recovered, and the player can choose to not place that device.

While a Cluster Mines set consists of 3 individual devices they are still part of a whole. If while dropping a Cluster Mine set one of the devices would be placed outside of the play area, the entire set cannot be placed.