Question: Undertow is a steel spinning roller coaster, built by Maurer Söhne, located at which oceanfront amusement park in Santa Cruz, California?

Context paragraphs:
Santa Cruz Beach Boardwalk: The Santa Cruz Beach Boardwalk is an oceanfront amusement park in Santa Cruz, California.  Founded in 1907, it is California's oldest surviving amusement park and one of the few seaside parks on the West Coast of the United States.

Giant Dipper: The Giant Dipper is a historic wooden roller coaster located at the Santa Cruz Beach Boardwalk, an amusement park in Santa Cruz, California.  It took 47 days to build at a cost of $50,000.  It opened on May 17, 1924, and replaced the Thompson's Scenic Railway.  With a height of 70 ft and a speed of 55 mph , it is one of the most popular wooden roller coasters in the world.  As of 2012, over 60 million people have ridden the Giant Dipper since its opening.  The ride has received several awards such as being named a National Historic Landmark, a Golden Age Coaster award, and a Coaster Landmark award; it has been ranked annually in Mitch Hawker's Best Wooden roller coaster poll.

Galaxy Orbiter: Galaxy Orbiter is a steel spinning roller coaster at Galaxyland amusement park in West Edmonton Mall, Edmonton, Alberta, Canada.  It was built by German manufacturer, Gerstlauer and is the first roller coaster of its type in Canada.  The ride officially opened on July 17, 2007.

Steel Dragon (Waldameer): Steel Dragon is a steel roller coaster that is located at Waldameer Park in Erie, Pennsylvania, United States.  This spinning roller coaster was manufactured by Maurer Söhne and opened in July 2004.

Sierra Sidewinder: Sierra Sidewinder is a steel spinning roller coaster located in the Camp Snoopy section of Knott's Berry Farm.  It is the first ever roller coaster to feature multiple free spinning cars on a train, rather than several individual spinning cars.  The only other spinning train coaster is Euro-Mir at Europa-Park in Germany, however the spinning of the trains is controlled throughout the ride.  It was also one of the first roller coasters to feature on-ride video recordings, as opposed to the traditional still on-ride photograph.  As of July 2016, the on ride video cameras have since been removed.

Giant Dipper (Belmont Park): The Giant Dipper, also known as the Mission Beach Roller Coaster, is a historical wooden roller coaster located in Belmont Park, a small amusement park in Mission Beach in San Diego, California.  The Giant Dipper was built in 1925.  The roller coaster and its namesake at the Santa Cruz Beach Boardwalk are the only remaining wooden roller coasters on the West Coast designed by noted roller coaster designers Frank Prior and Frederick Church.

Spider (roller coaster): The Spider is a steel spinning roller coaster made by Maurer Söhne of Germany.  The ride is located at the Lagoon Amusement Park in Farmington, Utah.  The Spider was installed at Lagoon in 2003, but shut down on opening day due to a wheel malfunction.  The ride re-opened one week later and has been running regularly since.

Spinball Whizzer: Spinball Whizzer is a spinning roller coaster located in the Adventure Land area of Alton Towers in Staffordshire, England.  Built by Maurer Söhne, it was previously sponsored by Sega, the company that created the "Sonic the Hedgehog" video game franchise, and was known as Sonic Spinball from 2010 to 2015.

Maurer AG: Maurer AG is a steel construction company and roller coaster manufacturer.  Founded in Munich, Germany in 1876, the company has built many styles of steel buildings, ranging from bridges, industrial buildings, and even art structures.  While known for building various wild mouse coasters, Maurer Söhne has been branching out into spinning, looping, and launching coasters recently.  The company also produces a free-fall tower ride.  On December 15, 2014, the company changed its name from Maurer Söhne GmbH & Co.  KG to Maurer AG.

Undertow (roller coaster): Undertow is a steel spinning roller coaster at Santa Cruz Beach Boardwalk.  , The ride was built by Maurer Söhne and is the only spinning roller coaster in Northern California.

Supporting paragraphs: Undertow (roller coaster) Santa Cruz Beach Boardwalk
Answer: Santa Cruz Beach Boardwalk