听力原文： The Sierra de Aracena in the northwest of Andalucia boasts one of the most beautiful rural landscapes in the region. One of the greenest comers of the sun-baked south, the peaks and valleys here are rich in forests of sweet chestnuts and cork oaks. In spring, wild flowers carpet the meadows, attracting a wealth of bird and insect life.
Despite its outstanding natural beauty, the Sierra de Aracena is barely touched by the tourist trail, and even Andalucians are largely unaware of its hidden treasures.
But take time to explore this region, and you're guaranteed not only space and tranquility, but the warmest of welcomes, particularly in the old-fashioned whitewashed villages, scattered throughout the highlands.
Peaks and valleys in the Sierra de Aracena are rich in ______.

A. forests of chestnuts and cork oaks
B. wild flowers
C. meadows
D. birds and insects