Workers originally formed unions: a) as social organizations. b) to protect themselves from intolerable work conditions and unfair treatment. c) as a way to increase job security and gain political power. d) to have the rights to strike and to picket.

Option 'b' is correct.

Explanation:

Workers originally formed unions with the help of which they can protect themselves from intolerable work conditions and unfair treatment such as low wage, late working hours, exploitation, unhygienic working condition, unsafe atmosphere etc.

And many workers had problems with their leaders or managers due to membership in unions.

Hence, Option 'b' is correct.