Which CSS3 style should you use?

You are developing a web page by using HTML5.
You have the following requirements:
An H1 element must be placed at the top left cornerof the page.
The size and location of the H1 element must not change if additional elements are added to the
page.
You need to position the H1 element on the page.
Which CSS3 style should you use?

A.

B.

C.

D.