[blml] L9A vs L73B1

[Jan Peter Pals]

East (dealer) opens 1C, not alerted. This may be a doubleton in a
5crd-major system and is alertable in the NL. Against this opening, NS
play an artificial defence, based on transfers.

South, who knows about the possible doubleton C, holds:

K9
62
QJ8
AKQ942

He would like to bid 1S (=transfer to clubs OR showing diamonds and
hearts). 
Over a 'natural' 1C (min. 3crd)  he would have bid 1NT.

South does not know what will happen: 
a) If he bids 1S, partner may not alert and jump to 3S. 
b) If he bids 1NT, partner may alert, explain spades and diamonds OR
hearts and clubs, and jump to 3H.

Is south allowed to ask the meaning, or draw attention to the
alertability of 1C?
If he doesn't, what are his options under the calamity scenarios in a)
and b)?

Thanks for comments
JP