Question

click to correct the pronoun if needed. pablo picasso and georges braque were the founders of the style known as cubism. to they and their fellow cubists, traditional artistic techniques were insufficient to portray the complexities of the modern world.

Explanation:

The preposition 'to' requires the objective - case pronoun. 'They' is a subject - case pronoun, and the correct objective - case form is 'them'.

Answer:

To them and their fellow cubists, traditional artistic techniques were insufficient to portray the complexities of the modern world.