Let's solve the problem step by step:

1. Determine Bola's original share:
- The ratio of Bola's and Tolu's shares is 5:8.
- The total value of the business is ₦1,300,000.
- The total ratio is $5+8=13$.

Bola's original share is:
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2. Calculate 20% of Bola's share:
- Bola is selling 20% of her share to Tolu.
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3. Determine Bola's new share after selling 20%:
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So, after selling 20% of her share to Tolu, Bola would own ₦400,000 of the business.

The correct answer is A. ₦400,000.