Both
Bitcoin because I don't have money to invest in gold unlike bitcoin,you can earn money here in joining bitcoin campaign and there are lot of oppurtunities here to become rich.
In the present age, if you know about bitcoin, then I dont really think so that you will even give a second thought before making this decision of investing your money into bitcoin.
Gold was once used to be a good way of investing money but now it is one and only bitcoin which is helping people to make their dream of getting rich come true. They are investing on bitcoin as they know this can help them in getting rich.