I am working on my university worksheet. I have no idea where I should ask this. I hope someone can help me out...

How do I name the following organic compound:
Ph-CH=CHPh  (the compound that gives only benozic acid as product when it reacts with O3 and acetone)

Thanks for whoever helps me out.

Either cis- or trans-1,2-diphenylethene (stilbene).