How do you solve Collatz conjecture

The Collatz conjecture, also known as conjecture , conjecture of Ulam or problem of Syracuse, is a conjecture of number theory established by Lothar Collatz in 1937 and says the following: If is an even number, divide it by 2 until you reach an odd number or 1, if is an odd number different from 1, multiply it by

Iwould have to say c. the german americans.