Organic Chem question.

You can do this on your own... K-tertbutoxide, hmm, BULKY BULKY *base*... what's going to happen? Check your SN1/SN2/E1/E2 criteria.

 

Remember, a bulky base will lead you to something sexy

 

Hoffmann vs Zaitsev...

 

You have two possible reactions that could occur. The first and the least likely route is the formation of an ether by way of Williamson Ether Synthesis (SN2 displacement of bromide). This type of reaction occurs most readily with primary alkyl halides due to minimal steric interference. The second and most probable pathway that can be followed is deprotonation of one of the protons on carbon 4 with simultaneous explusion of bromide (E2). The driving force for this E2 elimination comes from forming a conjugated pi system. The double bond formed is of the trans or "E" configuration. The cis or "Z" double bond is unlikely to form in any significant amount because the reaction would have to proceed through a transition state of higher energy.