District Mineral Foundations (DMFs) in India primarily serve one purpose as per the choices given.

Option 1 suggests that DMFs promote mineral exploration activities in mineral-rich districts. While it sounds reasonable, this is not the main purpose of DMFs. Their primary focus is not to promote mining activities but to ensure the welfare of the people and areas affected by such operations.

Option 2 is correct as it states that DMFs protect the interests of persons affected by mining operations. DMFs were indeed established with the aim of working for the benefit and rehabilitation of people and areas affected by mining related operations.

Option 3 also appears tempting, but the authorizing of State Governments to issue licenses for mineral exploration does not fall within the purview of DMFs. This is usually the responsibility of the central or state government mining departments.

In the light of these points, only option 2 correctly defines the objective of District Mineral Foundations in India. Options 1 and 3 are therefore incorrect, as they extend beyond the true purpose of DMFs. Accordingly, options that include them, namely options 1, 3 and 4, are incorrect. Hence, the provided answer "Option 2" is indeed correct.