VRK, an iconic actor, endorses several leading apparel and footwear li

VRK endorses several brands of apparel.
He plans to launch his own called VRX.
Advisers have said that if VRX does not meet quality expectations of customers, his brand value could be endangered.
Board said that VRX has quality required to enter competitive market.

Conclusion: VRK hopes that VRX will increase his overall revenue.

Note that the conclusion talks about increasing total revenue. So the earlier revenue should not suffer and there should be additional revenue (or additional revenue should more than make up for any loss in earlier revenue)

What will help us establish that overall revenue should increase?

A. most leading apparel and footwear manufacturers are not disinclined towards hiring a competitor as their brand ambassador

This helps. If most of the brands he endorses are disinclined towards hiring a competitor, his earlier revenue will see a big hit. So VRX may be competitive but its sale is unlikely to make up for a big hit.

B. in the past, all the brands that VRK has endorsed have earned commendable revenues for their manufacturers

Doesn't tell us what happens when VRK launches his own brand.

C. VRK’s reputation in the field of acting supersedes that of other actors who endorse similar brands

Irrelevant.

D. VRX products have been vouchsafed by the Quality Control Board as being better than those endorsed by VRK for other manufacturers

Does not matter. We know that VRX products have enough quality. We don't know how they will be priced. If they are priced higher than expected due to higher quality, we don't know whether they will sell. We also don't know whether his other endorsements will be fine with VRX. So we cannot say what may happen to overall revenue.

E. the general public is more inclined to purchase products endorsed by their icons than ones without such endorsements

All products we are talking about are endorsed by VRK hence irrelevant.

Answer (A)