Which of the following was the cause of the decline of Buddhism?

The important cause of the decline and fall of Buddhism was the decline of Buddhist Sanghas. The Sanghas became centres of corruption. The discipline of vinay pitaka was violated. The viharas were dominated by ease-loving people. The monks and nuns began to lead lives of pleasure and ease. The Mahayanist and Hinayanist quarreled with each other. Internal conflict proved to be the ruin of Buddhism.