Is it possible (or practical) to retake AS's which are 100% course work alongside A2?

[Lurgano]

Or can you retake just one module?
Ds only got a C for first AS art submission in Dec 14 - has been predicted a B overall for art AS - so assume that this second submission (April 15) was an A grade.... but he needs an A grade overall - so wondered if he could retake just the first Art AS assignment at the end of this year?

Similarly for Theatre Studies - could he just retake (if necessary) one unit e.g. the monolog