Final answer:
Dashes should be placed before and after 'for example' in the sentence to correctly set off the appositive phrase, making the complete sentence 'An intimidating guard animal—for example, the snaggle-toothed gopher—requires months of training.' The correct option is 1.
Step-by-step explanation:
The sentence 'An intimidating guard animal, for example, the snaggle-toothed gopher requires months of training.' should have dashes to set off the appositive phrase 'for example, the snaggle-toothed gopher.' The sentence should read: 'An intimidating guard animal—for example, the snaggle-toothed gopher—requires months of training.'
This correctly sets off the phrase and makes the sentence easier to read. Additionally, this follows the guidance from section 11.7 on dashes and parentheses, which suggests using dashes to emphasize or set off an appositive that includes commas. Therefore, the dashes go before and after 'for example.' The correct option is 1.