Why did Mikhail Gorbachev institute the policy of glasnost?

all of the above and to quell growing unrest by the proletariat, robotnics (workers) ruble was fluctuating in markets and unstable etc. Also Solidarity in Poland, Pocrepa (sp) in Bulgaria etc. forcing reforms by offering a vocal political opposition to the party hegemony. many underground newspapers were filling the streets with stories that the party had suppressed and so Glasnost was really an opportunity to advance the party by openly addressing some of the stories that were being put forth by the opposition and get their spin on them.