Step 1: Understand the meaning of RECTITUDE.
Rectitude means moral uprightness, righteousness, and strict adherence to honest and correct principles of conduct. A person of rectitude is someone whose behavior is beyond ethical reproach.
Step 2: Match it with the closest option.
Integrity means the quality of being honest and having strong moral principles, which is essentially the same idea as rectitude. Both words describe soundness of moral character.
Step 3: Eliminate the other options.
Immorality is the direct opposite of rectitude, describing a lack of moral principles. Fulmination means a loud protest or angry denunciation, an entirely unrelated idea about verbal outbursts, not character. Dissipation refers to wasteful or self-indulgent living, such as squandering money or health on pleasure, which is closer to the opposite of rectitude. Indulgence means allowing oneself excessive pleasure or leniency, again the opposite of disciplined moral conduct.
Step 4: Conclusion.
Integrity, option (d), is the correct synonym of rectitude.