Answer:
i would choose the first one
edit: actually nvm i think its the last one
<span>The correct option is B. Mike joined the Army, and he became more disciplined during the training. The correct way to connect these two clauses is to introduce a conjunction "and." A is incorrect because there should be a comma/conjunction between the words Army and he. C is incorrect because that semi colon is just randomly and incorrectly placed without a context. D is incorrect because there should also be the word "and" before "he."</span>
