Answer: D- making flexible eyeglass frames
Explanation: my powerful mind
The answer is Latitude (B)
In a solution of KBr and water; KBr is the solute and water is the solvent;
Therefore; to achieve 3% by mass; it means we are going to have 3% of the mass being the solute and the other 97 % being the solvent.
Thus; KBr (solute) = 3/100 × 300 (total mass) = 9 g
Hence; the appropriate masses will be; 9.00 g of KBr and 291 g of water.
Carbon-6 because it is a neutron number
The balloon's volume at 35°C : V₂=31.01 L
<h3>Further explanation</h3>
Given
T₁ = 25°C+273 = 298 K
V₁ = 30 L
T₂ = 35 °C + 273 = 308 K
Required
The new volume (V₂)
Solution
Charles's Law
When the gas pressure is kept constant, the gas volume is proportional to the temperature

Input the value :
V₂=(V₁.T₂)/T₁
V₂=(30 x 308)/298
V₂=31.01 L