The best answer is "was not part of the Eastern Bloc", although this answer is misleading.
Yugoslavia was indeed part of the Eastern Bloc in the sense that it was an Eastern European communist country, but it was the only one that did not align itself with the USSR after 1948. It also did no ally with the United States, choosing non-alignment instead.
This answer is the best answer simply because it is less false than the other answers, which are completely wrong. Yugoslavia never joined the USSR, choosing to split from Stalin in 1948, and never became a satellite nation of the US, and isn't located anywhere near the Baltic.
