Which one of the following statements concerning the General Public License (GPL) is true?

The fundamental design goal of the GPL is copyleft - any software distributed under the GPL must have its source code made freely available to recipients, and any derivative works must also be licensed under the GPL. This ensures software freedom is preserved through the distribution chain.

The BSD license is a permissive license that allows proprietary derivatives, while the GPL is a copyleft license that requires derivative works to remain open source - they are fundamentally different.

The GPL explicitly permits selling software for money; the requirement is only that source code must be made available to recipients, not that it must be free of charge.

The GPL does not require sending changes to the original author for approval; it requires that source code be made available to the recipients of the binary, with no approval gate from upstream authors.

The GPL places no restrictions on the purpose or domain in which software is used; usage restrictions of that kind appear in other licenses, not the GPL.