Answer:
2-methyl-butene
Explanation:
For the E2 mechanism, we have an anti-elimination. The Br leaves the molecule and the base removes the hydrogen in the anti position to form the double that's why only one structure is produced. (See figure 1)
Since we have 2 hydrogens on the right carbon, we cannot indicate a specific stereoisomer, in other words, it is not possible to assign a Z or E configuration for this alkene.