My attempt: I'm not sure this is right but this is what i did. I found the allele frequencies to be:
A=0.4 B-0.3 a=0.1 b=0.2
I think to find Dmax I just multiply the two alleles with the larges frequencies so it would be .4 * .3 = 0.12 (correct answers are in red). This method gives 0.12, but I'm not sure that's how the problem is done. (I can do the other parts).