For the purpose of expanding his business, Mr Zhang borrowed RMB 100,000 yuan from Mr Lee and would provide a mini-bus as the pledge to Mr Lee. However, Mr Lee returned the mini-bus to Mr Zhang because he did not hold a driver’s licence.Subsequently, Mr Zhang borrowed another RMB 100,000 yuan from Mr Wang and put the mini-bus as the pledge to Mr Wang. After the conclusion of the loan agreement and pledge agreement, Mr Zhang delivered the mini-bus to Mr Wang.During the period of his possession of the mini-bus, Mr Wang concluded a rental agreement with a transport company without the advance consent of Mr Zhang. The mini-bus was put into transportation service by the transport company but was totally destroyed in a traffic accident.Upon the expiration of the loan agreement, Mr Zhang came to repay the principal and interest. However Mr Wang could not return the pledged mini-bus to him.Required:Answer the following questions in accordance with the relevant provisions of the Property Law of China and give your reasons for your answer:

(a) explain whether the pledge agreement between Mr Zhang and Mr Lee came into effect; (3 marks)

导线为水平排列时，上层横担距杆顶距离不小于（）毫米。

A、100

B、200

C、300