 <translate> Q: Passage: The first season of Spring Baking Championship premiered on April 25, 2015. The second season of the series premiered on April 10, 2016, and concluded on May 15, 2016. The third season premiered on March 12, 2017, with Jesse Palmer replacing Deen as host. The fourth season premiered on March 12, 2018, with Ali Khan replacing Palmer as host.

Question: Based on this passage, who is the host of season 4 spring baking championship?
Let's give stream of consciousness below
 <yor> Q: Passage: Ìgbà àkọ́kọ́ ti Spring Baking Championship ni a ṣe àkọsílẹ̀ rẹ̀ ní April 25, 2015. Akoko keji ti jara naa ni iṣafihan ni Oṣu Kẹrin Ọjọ 10, Ọdun 2016, ati pari ni Oṣu Karun Ọjọ 15, Ọdun 2016. Akoko kẹta ti iṣafihan ni Oṣu Kẹta Ọjọ 12, Ọdun 2017, pẹlu Jesse Palmer ti o rọpo Deen bi oluṣe. Akoko kẹrin ti iṣafihan ni Oṣu Kẹta Ọjọ 12, Ọdun 2018, pẹlu Ali Khan ti o rọpo Palmer gẹgẹbi olugbalejo.  Ìbéèrè: Ní ìbámu pẹ̀lú àyọkà yìí, ta ni olùgbalejo ìdíje ìse búrẹ́dì ìgbà ìrúwé kẹrin? Ẹ jẹ́ kí a fún ìsun ìmọ̀lára ní ìsàlẹ̀ 