Answer:
(Z)-(2-methylbut-1-en-1-yl)benzene
Explanation:
In the E2 elimination reaction, we will have a <u>single-step mechanism</u>. In this single step, we need an <u>anti-peri-planar geometry</u>. In other words, we need a specific configuration for the <u>leaving group</u> and the <u>H that would be removed</u>. These 2 atoms must have an opposite configuration when the base attacks the hydrogen.
With this in mind, we have to <u>rotate</u> the molecule in order to obtain the desired geometry (see figure). When we do this, the <u>methyl group</u> would be placed on <u>top</u> and the <u>ethyl group</u> at the <u>bottom</u>.
Finally, when the elimination takes place (<u>blue arrows</u>) the configuration of the final alkene would be "Z" due to the previous rotation that we did in order to obtain the correct configuration for the elimination.