Why did people from Russia and Baltic areas feel alienated from the C…

The correct answer is Option (3) → The economic price to keep the more backward areas within the Soviet Union was too high

Option (1) High military spending on nuclear arsenals in Central Asia. — Incorrect. The Soviet economy did spend much of its resources on its nuclear and military arsenal and on its satellite states, but that was a burden on the whole system. The people of Russia and the Baltic areas felt alienated because they were paying for the more backward areas, not because of arms spending.

Option (2) Disillusionment with Brezhnev’s Asian Collective system. — Incorrect. Leonid Brezhnev, the Soviet leader from 1964 to 1982, proposed an Asian Collective Security system, a plan in foreign policy. It had nothing to do with why the people of Russia and the Baltic areas felt alienated from the Central Asians.

Option (3) The economic price to keep the more backward areas within the Soviet Union was too high — Correct. People in Russia and the Baltic areas felt alienated from the Central Asians and concluded that they were paying too high an economic price to keep the more backward areas within the Soviet Union.

Option (4) Coup was staged by Central Asians in Baltic region in 1991. — Incorrect. The coup of August 1991 was an abortive one by Communist Party hardliners, not by Central Asians.