Kyphosis is an excessive forward curve of the upper spine, so the corrective principle is simple: the ideal asanas must be backbends that extend the spine backward and open the chest, and any set containing a forward-bending pose should be ruled out immediately.
- Chakrasana, Trikonasana, Adhomukhasana: Trikonasana is a lateral (sideways) stretch and Adhomukhasana (Downward-Facing Dog) is a forward-folding, inverted-V posture, neither of which extends the upper spine backward the way kyphosis correction requires; only Chakrasana in this set is a genuine backbend, so the set as a whole is incorrect.
- Dhanurasana, Bhujangasana, Halasana: Dhanurasana and Bhujangasana are both strong backbends and would help, but Halasana (Plough Pose) folds the spine forward over the head, which works against the backward correction kyphosis needs, so this set fails the backbend test on its third asana.
- Bhujangasana, Trikonasana, Chakrasana: Bhujangasana and Chakrasana are backbends, but Trikonasana is a lateral stretch rather than a spinal extension, so it does not target the forward-rounding of the upper back that defines kyphosis, and this set fails too.
- Dhanurasana, Chakrasana, Bhujangasana: All three of these are backbends. Dhanurasana arches the whole spine and opens the chest, Chakrasana produces a deep full-body backward bend, and Bhujangasana specifically strengthens and extends the upper back and thoracic spine. Every asana in this set satisfies the backward-extension requirement.
Applying the single test of "does every asana in the set bend the spine backward and open the chest" eliminates every option except the one where all three poses are genuine backbends.
Therefore, the correct answer is Dhanurasana, Chakrasana, Bhujangasana.