Correct Answer: Bolster

Solution : The correct choice is the fourth option.

Support and bolster both imply strengthening, reinforcing, or providing assistance to something or someone. In the context of aiding or reinforcing, bolster is the correct synonym for support .

The meanings of the other options are as follows:

• Release: To set free, let go, or allow something to become available.
• Refuse: To decline or reject something.
• Spine: The series of vertebrae forming the axis of the skeleton; backbone. In a figurative sense, it can refer to inner strength or resilience.