a. roman catholics
Roman catholicism is the most abundant religion in the area, although the region also has sizable populations of Catholics and Muslims and notable shares of Lutherans in some countries. However Catholicism remains the most predominant religion in the west of Eastern Europe. The most representative cases of this are Austria, and Poland. While, in the Czech Republic is the only country surveyed in which a majority of older people say they are religiously unaffiliated,still , there is a tendency back to religion in some areas among eldery and other social groups. Slovenia, Slovakia,etc also have considerable amounts of catholic devotes.
Both implies two so your answer is two
