Why is the slow growth that can result from a contractionary policy a positive effect? it can increase interest rates. it can decrease available credit. it can increase the money supply. it can decrease inflation.

I believe the answer is: it can decrease inflation

Contractionary monetary policy refers to the economic policy that is aimed to decrease the money supply that circulated in the market.
When the amount of money is decreased, it's rarity cause that specific currency to increase in value, which would lead to the decrease in inflation

It can decrease inflation