Actually starting a business with 100k is not feasible given the inflation rate @'17% which means your money is depreciating daily.
If you are in Nairobi then the money disappears faster once it's off the bank
Id rather you buy a capital item that can generate income at home or on the go.
if you have acess to farmland plant a high value, four months maturing crop.talk to me I except to earn 200k from an investment of 70k in 5 months time.
So dont go into biashara yet but invest first. Good luck