Which of the following main clauses indicates that the subordinate second clause will need to be in the subjunctive?
1.) es bueno
2.) yo tengo una perra
3.) el papel es blanco
4.) el juez superior

The subjunctive expresses an attitude of the person with respect to someone or something. In general, it needs another verb that determines the meaning of that attitude. It is often used in subordinate sentences that begin with the word QUE, In this case the main clauses that contains que and we expect to express an attitude  is option 1. Es bueno que ...