The Leader of the Opposition of Singapore is usually the leader of the second largest political party represented in the Parliament of Singapore. During the 1955 Legislative Assembly election, the late Lee Kuan Yew was the "de facto" Leader of the Opposition, as the People's Action Party was then the second largest political party represented in the Legislative Assembly.
Can we infer the following?
The Leader of the Opposition of Singapore was firstly elected during the 1955 Legislative Assembly Election

Choose from:
 --Yes.
 --It's impossible to say.
 --No.
The answer is:
It's impossible to say