现判断下列句子属于哪一种语言风格，并在各句后面分别标上a，b

题目描述

现判断下列句子属于哪一种语言风格，并在各句后面分别标上a，b，e，or d：a)impersonal，formal and very sureb)personal and unsurec)impersonal and very sured)personal and informal1)I think we should go ahead and invest in this pmject.If we don’t， we’11 be missing a golden opportunity.2)Investment in this project is imperative.Failure to invest would mean a missed opportunity.3)No time should be wasted in advertising the post.Any delay will certainly result in less efficiency.4)We should consider advertising the post.If we don’t，it could lead to a reduction in efficiency.