提出建议：Let's... — 英语选择题

Tom 对你说："It's raining. We can't play outside." 你想建议他一起在家里下棋（play chess），下面哪一句是最恰当的 Let's 建议？A. Let's to play chess at home. B. Let's playing chess at home. C. Let's play chess at home. D. Let play chess at home.