By 1987, CBS was the only "big three" American TV network to have a co-owned record company. ABC had sold its record division to MCA Records in 1979, and in 1986, NBC's parent company RCA was sold to General Electric, who then sold off all other RCA units, including the record division (which was bought by Ariola Records, later known as BMG).
RCA's parent company NBC was sold to whom ?