According to general rule, the first word in every sentence should begin with a capital letter. The letter 'I', when referring to yourself should also be capitalized in every sentence.
When a dependent clause is followed by an independent clause, a comma is required.
Thus, according to the rules, the correct answer is Option B. The remaining options are incorrect.
Option C - Using all capital letters in a sentence indicates high volume or expression of anger, so it should be avoided.