Answer:
The correct direction is B.
Step-by-step explanation:
Both masses are pulling the block with forces equal to their weights. Since the mass of 250g is greater its weight is greater too, so the force exerted to the block is also greater. A greater force means a greater acceleration, this indicates that the block gains speed faster to the right, this indicates that options C and D are incorrect. Since the block is still being pull by the 100g mass option A is incorrect too. This means that the correct answer is B.