The correct answer is the following.
Leonardo observed the work of Verrocchio the religious motives in his paintings and the sculptures he created for many clients. He made a lot of works for Piero and Lorenzo de' Medici. Leonardo, as an apprentice of Verrocchio, learned the designs and ways to do business of his teacher.
Andrea del Verrocchio (1435-1488) was a famous sculpture that created beautiful pieces of work in the painting too. Probably, his most famous creation is in Venice, Italy. It is the equestrian statue of Bartolomeo Colleoni.