I have a few question about MC/DC and piarwise testing

Recently, I started working on software testing, and I had some questions.

Pairwise testing is the combination of all the values ​​that this parameter can have, and is it also applicable to Boolean Expression?

For example,

boolean expression is (A || B) && C (It is assumed that each parameter has only 0 and 1.)

Here, Is it applicable to Boolean Exp ??

Second question is about MC/DC.

I had learned how to make test case through MC/DC

But, I wondered how MC/DC could prove to cover almost 90% code code coverage ?

In (A || B) && C, there are 4 combination test case in my guess.

But, All combination is 8. how could MC/DC reduce cases ?