Can generations 1-4 programming languages be object-oriented programming language?
First-generation is binary, just zeros and ones, so you can not talk about OOP at this level. The same is true, no OOP, for the second-generation languages, assembly languages. Third-generation languages include C++ and Java, so, YES, you can say that a third generation language can be OOP. Fourth-generation languages can include OOP features, but tipically they are closer to human language and are not intended to be OOP. Fifth-generation languages are used mainly in artificial intelligence research, so, no OOP. More about it you can find at http://en.wikipedia.org/wiki/Programming_language.