Final answer:
The subject of this question is physics and the correct option is C) Pulleys, which are used to connect objects and can be used to multiply force or change the direction of a force.
Step-by-step explanation:
The subject of this question is Physics. The question is asking about the type of connections used for three identical blocks. The correct option is C) Pulleys. Pulleys are used to connect objects and can be used to multiply force or change the direction of a force.