I stil have not worked out why having a line feed at the end should add quotes around the concatenated string. I am asking on experts exchange.
http://www.experts-exchange.com/Applications/MS_Office/Excel/Q_21840323.html
But even if it means globally replacing " with zilch I think that I prefer it, especialy when we remove the grey columns, adding the control characters in the concatenate which becomes
=CONCATENATE("::",A2,"::",B2,"{",CHAR(13),CHAR(10),"=",C2,CHAR(13),CHAR(10),"~",D2,CHAR(13),CHAR(10),"~",E2,CHAR(13),CHAR(10),"~",F2,CHAR(13),CHAR(10),"}",CHAR(13),CHAR(10))
Additionally, as far as I know, feedback screens in moodle still display the answers (A,B,C,D) in the same order that they appear in the GIFT file. Hence if the correct answers is always the first answer then students will be able to get the correct answer on the second attempt. So introducting four IF statements and a random number will put the right answer in a random position.
Please see attached.