horizontal line and right way to code it in html css

Question

I need to draw a horizontal line after some blocks, and I have three ways to do it:

1) Define a class h_line and add CSS features to it, like

#css
.hline { width:100%; height:1px; background: #fff }

#html
<div class="block_1">Lorem</div> <div class="h_line"></div>

2) Use hr tag

#css
hr { width:100%; height:1px; background: #fff }

#html
<div class="block_1">Lorem</div> <hr />

3) use it an after pseudoclass

#css
.hline:after { width:100%; height:1px; background: #fff; content:"" }

#html
<div class="block_1 h_line">Lorem</div>

Which way is the most practical?