 Complete the following phrase:  Bett began to compete on the international track and field circuit in 2015 and had wins at the Savo Games and Lappeenranta Games in Finland. A personal best of 48.29 seconds at the 2015 Athletics Kenya World Championship Trials brought him selection for the national team and raised him to third on the global rankings. At the 2015 World Athletics Championship in Beijing, Bett achieved his biggest result, winning 