Question: From which Metallica album does the song, used by Niels de Ruiter as walk-on music, come?

Related documents: [0]  [DOC] "Enter Sandman" is a song by American heavy metal band Metallica. It was released as the first single from their eponymous fifth album, "Metallica" in 1991. The music was written by Kirk Hammett, James Hetfield and Lars Ulrich. Vocalist and rhythm guitarist Hetfield wrote the lyrics, which deal with the concept of a child's nightmares. [END] 
[1]  [DOC] On the darts circuit his nickname is The Excellent Dude, which is a reference from the film "Bill & Ted's Excellent Adventure". He is also known for using Metallica's 'Enter Sandman' as his walk-on music, which he plays air guitar as he enters the stage. [END]  
Answer: Metallica
Metallica