The subjunctive is a grammatical mood that expresses suggestions, wishes, etc. It also expresses doubts. When a sentence does not express doubt. The grammatical mood is not subjunctive.
E.g.
•Dudo que tengas dinero para mi almuerzo.
This sentence expresses doubt.
Whereas..
•No dudo que te mantienes en buena forma física.
The sentence does not express doubt.
the answer is A i must believe
Saber is knowing and concur is meeting. Hope this helps :)
The answer is true :) I hope this helps
I believe it is D.
Hope this is of help to you, and happy studying~!
~{Oh Mrs.Believer}