Which practice regulates advertising to children by limiting the times commercials can air?

The practice that regulates advertising to children by limiting the times commercials can air focuses specifically on protecting younger audiences from excessive and potentially manipulative advertising practices. This regulation aims to ensure that children are not exposed to advertisements during vulnerable times, such as when they are most likely to be watching television—often during children's programming.

By limiting the times when commercials can air, the regulation seeks to create a safer media environment for children, taking into account their developmental stages and the influence advertising can have on their perceptions and wants. This measure aligns with broader efforts to promote responsible advertising practices and supports the idea that children may not fully comprehend the intent of commercial messaging.

In contrast, the other options do not directly relate to regulating advertising to children. Maintaining a play area in bookstores focuses on enhancing a customer-friendly environment rather than addressing commercial limits. Placing newspaper fundraising ads pertains to promotion and funding initiatives, while offering coupons on websites is a marketing strategy that does not specifically involve the timing of commercials or target children's advertising directly.