The reason---I'm writing is that I want to tell you about a party_英语解答

The reason---I'm writing is that I want to tell you about a party on Saturday.
A because B why C for D as

人气：117 ℃　时间：2019-09-25 13:57:22

解答

B
The reason 后跟定语从句I'm writing,我写信的原因是.
如果是短语的话就跟for
reason 的固定句型：
The reason + why +定从+is that +.
The reason +for +短语+is that +.
That is because.
That is why.