Question: What had four separate designs and replaced The PowerBook and iBook lines?
Context: The Sudden Motion Sensor (SMS) is Apple's motion-based data-protection system used in their notebook computer systems.  Apple introduced the system January 1, 2005 in its refreshed PowerBook line, and included it in the iBook line July 26, 2005.  Since that time, Apple has included the system in all of their portable systems (since October 2006), now the MacBook Pro and MacBook Air. Old World ROM computers are the Macintosh (Mac) models that use a Macintosh Toolbox read-only memory (ROM) chip, usually in a socket (but soldered to the motherboard in some models).  All Macs prior to the iMac, the iBook, the Blue and White Power Mac G3 and the Bronze Keyboard PowerBook G3 use Old World ROM, while said models, as well as all subsequent models until the introduction of the Intel-based EFI Models, are New World ROM machines.  In particular, the Beige Power Mac G3 and all other beige and platinum-colored Power Macs are Old World ROM machines.  In common use, the "Old World" designation usually applies to the early generations of PCI-based "beige" Power Macs (and sometimes the very first NuBus-equipped models), but not the older Motorola 68000-based Macs; however, the Toolbox runs the same way on all three types of machines. The PowerBook (known as Macintosh PowerBook before 1997) was a line of Macintosh laptop computers that was designed, manufactured and sold by Apple Computer, Inc. from 1991 to 2006.  During its lifetime, the PowerBook went through several major revisions and redesigns, often being the first to incorporate features that would later become standard in competing laptops.  The PowerBook line was targeted at the professional market, and received numerous awards, especially in the second half of its life, such as the 2001 Industrial Design Excellence Awards "Gold" status, and Engadget's 2005 "Laptop of the Year".  In 1999, the line was supplemented by the consumer iBook range.  The PowerBook and iBook lines were discontinued and replaced by the MacBook Pro and MacBook families respectively by 2006. The MacBook family is a brand of Macintosh laptop computers by Apple Inc. that merged the PowerBook and iBook lines during Apple's transition to Intel processors.  The current lineup consists of the MacBook (2006–2012; 2015–present), the MacBook Air (2008–present), and the MacBook Pro (2006–present).  The MacBook and redesigned MacBook Pro are the only MacBooks that do not incorporate the use of a MagSafe charger, but rather a USB Type-C port. The PowerBook 140 was released in the first line of PowerBooks.  It was the mid-range PowerBook, between the low-end 100 and the high-end 170.  As with the PowerBook 170, and unlike the 100, this PowerBook featured an internal floppy drive.  Codenames for this model are: Tim Lite, Tim LC, Replacements, and Leary.  In 1992, it was replaced by the PowerBook 145, which was essentially a speed bump, though the PowerBook 160 essentially superseded it as the new mid-line model. There have been four separate designs of the MacBook.  The original model used a combination of polycarbonate and fiberglass casing which was modeled after the iBook G4.  The second type was introduced in October 2008 alongside the 15-inch MacBook Pro; the MacBook shared the more expensive laptop's unibody aluminum casing, but omitted FireWire.  A third design, introduced in late 2009, had a polycarbonate unibody casing. The iBook is a line of laptop computers designed, manufactured, and sold by Apple Inc. from 1999 to 2006.  The line targeted entry-level, consumer and education markets, with lower specifications and prices than the PowerBook, Apple's higher-end line of laptop computers.  It was the first mass consumer product to offer Wi-Fi network connectivity, which was then branded by Apple as AirPort. Monégasque euro coins feature two separate designs for the first two series of coins, and also two separate designs for the €1 and €2 coins for the first series.  All the coins are inscribed with the word "Monaco" and the twelve stars of Europe.  The Monégasque euro coins are minted by the Monnaie de Paris (Paris Mint). The PowerBook G4 is a series of notebook computers manufactured, marketed, and sold by Apple Computer, Inc. between 2001 and 2006 as part of its PowerBook line of notebooks.  The PowerBook G4 runs on the RISC-based PowerPC G4 processor, designed by the AIM (Apple Inc./IBM/Motorola) development alliance and initially produced by Motorola.  It was built later by Freescale, after Motorola spun off its semiconductor business under that name in 2004.  The PowerBook G4 has two different designs: one enclosed in a titanium body with a translucent black keyboard and a 15-inch screen; and another in an aluminum body with an aluminum-colored keyboard, in 12-inch, 15-inch, and 17-inch sizes. The PowerPC 7xx is a family of third generation 32-bit PowerPC microprocessors designed and manufactured by IBM and Motorola (now Freescale Semiconductor).  This family is called the PowerPC G3 by its well-known customer Apple Inc., which introduced it on November 10, 1997.  The term "PowerPC G3" is often, and incorrectly, imagined to be a microprocessor when in fact a number of microprocessors from different vendors have been used.  Such designations were applied to Macintosh computers such as the PowerBook G3, the multicolored iMacs, iBooks and several desktops, including both the Beige and Blue and White Power Macintosh G3s.  The low power requirements and small size made the processors ideal for laptops and the name lived out its last days at Apple in the iBook.
Answer: MacBook