Answer: Consider a vote in favor of school uniforms.
An e-mail subject line should explain what the e-mail is about, and while it should create some suspense regarding the details of it, it should not present incomplete information.
Option 4 is extremely vague, as it does not mention any of the relevant topics of the email. The second option is slightly closer, but it still provides very little information. Option one adresses the topic of uniforms more clearly, but does not explain what it wants the reader to do, therefore, the reader might be tempted to not read it. Option three addresses the topic of uniforms, establishes the position of the author (pro-uniforms) and explains what the reader is encouraged to do (vote for school uniforms).
