The correct answer is [B] are always arguing
We can use always with present continuous to show how we feel (approve, disapprove, like, dislike, etc.) about something that happens regularly.
Some grammar books refer to this use as present continuous with “emotional comment.” It tells what happens regularly, but also gives the speaker’s attitude about the sentence. The action happens regularly or all the time, but we use the present continuous with always/constantly/continuously/forever, etc. to show how we feel about it. This makes it different from just stating a fact about what happens regularly in simple present tense.
We use always in simple present tense to describe habitual or everyday activities.
• Demi always leaves for school at 7:45.
• Juliar always has coffee for breakfast.
In a special circumstances, a speaker may use always with the present continuous to complain, to express annoyance, or anger.
• Juliar always leaving her dirty clothes on the floor for me to pick up! Who does she think I am? Her maid??