Past simple or present perfect

Hi, Yama, and nice to see you here again,

@Yama posted:

It ........ yesterday. It's muddy outlside.

1)rained     2)has rained     3)rains     4)rain

Obviously, we should choose either 1 or 2

What confuses me is that there is a time reference( yesterday) and there's also  a present result in the second sentence. So, should I use "rained" because of yesterday or "has rained" because of the present result ?

Thanks in advance.

What is the source of this question? With 'yesterday', go with '1) rained'.

Thanks ahmed. I really don't remember which book . Thanks again.

@Yama posted:

It ........ yesterday. It's muddy outlside.

1)rained     2)has rained     3)rains     4)rain

Obviously, we should choose either 1 or 2

What confuses me is that there is a time reference( yesterday) and there's also  a present result in the second sentence. So, should I use "rained" because of yesterday or "has rained" because of the present result ?

Hello, Yama and Ahmed—As a native speaker, I never feel constrained by the answer choices on grammar exercises that are brought to this forum. In this case, the natural choice would be "must have rained":

• It must have rained yesterday. It's muddy outside.
• It's muddy outside. It must have rained yesterday.