The correct answer is B because the advantages of a SPAC exit include:

1. Flexibility in the transaction structure to best suit the company's context.
2. Fixed valuation with lower volatility of share pricing.
3. Extended time for public disclosure on company prospects to build investor interest.
4. Association with high-profile sponsors and their extensive investor networks.

Option A is incorrect because while fixed valuation is an advantage, it is not the primary advantage of flexibility. Option C is incorrect because redemptions are allowed in SPACs, which can increase deal risk, and restrictions on redemptions are not a typical advantage.