which of the following does not exhibit cis or trans?

What does one look for in answering this?

which of the following does not exhibit cis or trans?

What does one look for in answering this?

This link explains some good and basic stuffs on cis and trans, and even tells when to use E-Z notation:

http://www.chemguide.co.uk/basicorg/isomerism/geometric.html

Beyond that like the one you see in Achiever may further be explained through the link below under Examples of Alkenes # 15:

http://www.wpbschoolhouse.btinternet.co.uk/page06/AlkeneStructure.htm

where geometrical isomers cease to occur when two identical groups (R, X, etc) are attached to the same carbon of the double bond.

I am pretty sure that its asking what figure displays e or z not cis and trans.