The correct answer is (b).
A foehn is a warm, dry downslope wind that occurs in the lee of mountains. It is caused by the adiabatic warming of air as it descends the mountain slopes. Foehn winds are common in the Alps, the Rocky Mountains, and the Andes.
A bora is a cold, dry wind that blows down the eastern slopes of the Alps. It is caused by the passage of cold air from the Arctic over the mountains. Bora winds are common in the winter and can reach speeds of up to 100 miles per hour.
A mistral is a cold, dry wind that blows down the Rhone Valley in France. It is caused by the passage of cold air from the Alps over the valley. Mistral winds are common in the winter and can reach speeds of up to 50 miles per hour.
A khamsin is a hot, dry wind that blows from the Sahara Desert into Egypt. It is caused by the passage of a low-pressure system over the desert. Khamsin winds are common in the spring and can reach speeds of up to 50 miles per hour.
The only pair that is not correctly matched is (b). The bora is a cold, dry wind that blows down the eastern slopes of the Alps, not Siberia.