2 mangoes = 3 apples, 2 apples = 4 bananas, so instead of buying 3 mangoes, how many bananas are available?

Given:
1. $2 \text{ mangoes} = 3 \text{ apples}$
2. $2 \text{ apples} = 4 \text{ bananas}$

From the first equation:
$1 \text{ mango} = \frac{3}{2} \text{ apples}$

From the second equation:
$1 \text{ apple} = 2 \text{ bananas}$

Now, let's find out how many bananas are equivalent to 3 mangoes:

Using the above conversions:
$3 \text{ mangoes} = 3 \times \frac{3}{2} \text{ apples} = \frac{9}{2} \text{ apples}$

Now, converting apples to bananas:
$\frac{9}{2} \text{ apples} = \frac{9}{2} \times 2 \text{ bananas} = 9 \text{ bananas}$

∴ Instead of buying 3 mangoes, 9 bananas are available. The correct option is 3) 9 bananas.