The correct answer is option 3, Brahmacharya—Grihasthashrama— Vanaprastha — Sanyasa. These are the four stages (Ashramas) of life in Hindu philosophy and they developed during the post-Vedic period.

Option 1, Dharma — Artha — Kama — Moksha, are the four aims (Purusharthas) of life according to Hindu philosophy. They were present both in the Vedic and later periods.

Option 2, Brahmana—Kshatriya—Vaishya—Shudra, represents the Varna system, or the social classes, which was already developed in the Vedic times, therefore it`s not a post-Vedic development.

Option 4, Indra — Surya — Rudra — Marut, are Vedic gods. Their worship was prevalent during the Vedic period itself, therefore, their usage is also not a post-Vedic development.

On the other hand, "Brahmacharya—Grihasthashrama— Vanaprastha — Sanyasa" were stages that were identified in life during the post-Vedic period and hence, is the correct answer.