The correct answer is A) poor farmers.
The group of people that would have been most likely to support Watson and the Populist Party were poor farmers.
Thomas E Watson (1856- 1922) was a politician from Georgia that became the leader of the solid organization called Farmers' Alliance, although he never was a member of the alliance; he just supported its ideals. Farmers' Alliance demanded the abolition of national banks, to end speculation of farm commodities, and the return of lands that had been granted to private hands.
The other options of the question were B)urban professionals. C) rich industrialists. D) suburban middle class.