Apple Computer Inc yesterday unveiled its newest Macintosh for educational market. The LC 520 offers built-in CD-ROM, high-quality stereo sound and exceptional colour display in an all-in-one design. In the US, the LC 520 will be available only to schools and higher education institutions. Elsewhere, it will be offered only in Canada and in Japan. The 25MHz 68030-based LC 520, derived from the LC III, comes with 5Mb to 36Mb and an 80Mb disk, 14 Sony Corp Trinitron colour display, internal AppleCD 300i double speed CD-ROM drive, integrated headphone jack and omnidirectional microphone. It is $1,510 and $90.30 for the Apple Keyboard II. The Macintosh Math Co-processor is $65, Ethernet LC Card at $140 and the Apple IIe Emulation Card at $125.