For a self-mailer folded at the bottom, how many tabs must it have regarding fastening?

A self-mailer folded at the bottom must be secured properly to maintain its integrity during handling and delivery. The requirement for two tabs is grounded in postal regulations to ensure that the mailpiece is securely closed and does not open unintentionally.

Having two tabs creates additional support to keep the self-mailer folded, which is particularly important since it will be traveling through various postal processing systems. The two tabs must be placed strategically to ensure that the mailpiece does not malfunction, ensuring it can withstand the rigors of mailing without risk of it coming apart.

The other options do not meet the postal requirements: having only one tab does not provide sufficient security, while suggesting one to two tabs or three tabs may imply an unnecessary complication either in fastening or exceeding the required standard. Therefore, the specification of two tabs as the correct answer reflects postal regulations aimed at ensuring that self-mailers are processed smoothly and safely.