If I would had 10 thousand dollars, I would invest in bitcoin, because with such a sum you can invest in bitcoin and even need it to invest only in bitcoin with big amount. I might also have thought about investing in tether or stellar.
It is obvious that investing in bitcoin all of that money is not a bad choice but it is the most obvious one that you can make in this market and if you really want to multiply the amount of profits that you want to get then it is better to invest in altcoins that you know that can give you great profits but that are secure enough to hold for the long term.