Answer: C is correct
Explanation: Europeans were able to defeat Muslim armies ...both in early Middle Ages (8th century Charles Martel, battle of Poitiers/Tours) and later they were succesful in Iberian peninsula (reconquista: first in Portugal and then in Spain: in 1492 finally expelled from the peninsula). However, Turks were able to defeat Christians in Constantinople (1453) and since then there is no Constantinople but Istambul. Moreover this conquest later became point of departure for Turkish expansion to the Balcans.