TASK DEFINITION: You are given a science question (hard-level) and four answer options (associated with "A", "B", "C", "D"). Your task is to find the correct answer based on scientific facts, knowledge, and reasoning. Do not generate anything else apart from one of the following characters: 'A', 'B, 'C', 'D'. There is only one correct answer for each question.
PROBLEM: How does a parachute sufficiently increase air resistance to allow the parachutist to land safely?   
 (A) by decreasing the force of gravity acting on the parachutist (B) by decreasing the total mass of the parachutist (C) by increasing the surrounding air pressure around the parachute (D) by increasing the total surface area of the parachute

SOLUTION: D

PROBLEM: A combination of processes occurs when stars are forming. Which is one process most likely associated with the formation of new stars?   
 (A) Hydrogen in the cores of the stars is exhausted. (B) Material accumulates from stars that have died. (C) Elements in the stars such as iron undergo fusion. (D) Cores of stars become twice as massive as the Sun.

SOLUTION: B

PROBLEM: Sound is able to travel faster in solids than in air because the molecules in a solid are  
 (A) closer together than air molecules. (B) more easily moved than air molecules. (C) moving faster than air molecules. (D) larger than air molecules.

SOLUTION:
A