The correct option is A Because
The given sentence is a complex sentence. That is, it is made up of a main clause "He asked for a bank loan" and a subordinate clause "he didn't have sufficient resources". The latter depends on the former for its complete meaning. The latter states a reason. They are to be connected with the help of a conjunction.
Option D: 'Also' means 'in addition to'. It refers to an addition whereas a conjunction that refers to the relation between the clauses (expressing reason) is required. Hence the word must be replaced and option D is incorrect.
Option A: 'Because' means 'for the reason that'. It is relevant to the statement because the subordinate clause is the reason behind which the action in the main clause "asked for a bank loan" takes place. Hence A is correct.
Option B: 'Even if' expresses a contrast, whereas the sentence focuses on reason. Hence B is incorrect.
Option C: 'Requiring' means 'need for a particular purpose'. It does not express reason, nor does it function as a conjunction. Hence C is also incorrect.