Activity

Taking all 3 multiple choice tests at the same time is doable, but a lot depends on the individual.
Are you over-worked? (Sadly those employed generally are, due to the “attrition” the profession has experienced)
Do you have kids, significant others, sick parents, do a lot of onerous volunteer work?
How focused are you at test preparation?
 
If you can answer no, no, and pretty good, then you are a candidate for taking all three at the same time. Otherwise A&B followed by D or vice-versa, might be a better plan. D covers a lot of ground.