The statement that best explains the development of constitutional monarchy in England is:
"The idea that a monarch’s powers should not be absolute was first made law in the Magna Carta, and with the Glorious Revolution it became the basis of England’s monarchial system."
This statement accurately captures the evolution of constitutional monarchy, highlighting the foundational role of the Magna Carta in limiting the powers of the monarchy and how the Glorious Revolution further solidified this concept, leading to a system where the monarchy's powers were defined and restricted by constitutional law.