(a) The tree diagram is as follows:

- First branch: Pizza (0.35), Burger (0.44), Curry (0.21)

- Second branch for Pizza: Fruit (0.3), No Fruit (0.7)

- Second branch for Burger: Fruit (0.8), No Fruit (0.2)

- Second branch for Curry: Fruit (0), No Fruit (1)

(b) The probability that Rani has some fruit is calculated as:

\(0.35 \times 0.3 + 0.44 \times 0.8 + 0.21 \times 0 = 0.105 + 0.352 + 0 = 0.457\)

(c) The probability that Rani does not have a burger given that she does not have any fruit is:

\(P(\text{not B} | \text{not fruit}) = \frac{P(\text{not B} \cap \text{not fruit})}{P(\text{not fruit})}\)

Calculate \(P(\text{not B} \cap \text{not fruit}) = 0.35 \times 0.7 + 0.21 \times 1 = 0.245 + 0.21 = 0.455\)

Calculate \(P(\text{not fruit}) = 1 - 0.457 = 0.543\)

Thus, \(P(\text{not B} | \text{not fruit}) = \frac{0.455}{0.543} = 0.838\)