Mathematics tools

Hi.
I made a Stack question with an input type "Radio" and I've set "LaTeX" for Extra Options because the student must choose in a list of CAS expressions.
The setting of multiplication notation is ok for the question text (before the list of the radio button : I chose "None") but not for the CAS expressions in the list : LaTeX uses the point notation.

Any idea to help me ?

Thanks a lot.

Laurent ; Stack 3.5

PS:
Question variables is this question
a:rand(10)+1;
b:rand_with_prohib(1,10,[a]);
e:a^2*x^2-2*a*b*x+b^2;
e1: (a*x-b)^2;
e2: (a*x+b)*(a*x-b);
e3: (a*x+b)^2;
ta: [ [e1,true],[e2,false],[e3,false] ] ;
/* La réponse correcte    */
tac:e1;

/* Permutation aléatoire de la liste ta */
ta: random_permutation(ta);
/* On ajoute "Autre expression" à la fin de la liste. La valeur retournée à Maxima est null, et on affiche le mot "Autre expression" dans la question. */
/*tao: [null, false, "Pas de solution"]; */
/* ta :append(ta,[tao]); */

Question Text :
La forme factorisée de @e@ est : [ [input:ans1] ] [ [validation:ans1] ]