A group of students: Alex, Ben, Clara, Diana, and Ethan are to be selected based on the following conditions: 1) At least two students must be selected. 2) Alex and Ben cannot be selected together. 3) Clara must be included if Diana is included. Which of the following selections is valid?

A. ALEX, CLARA, ETHAN

In a group of five friends: Alice, Bob, Charlie, David, and Eva, the following conditions apply: 1) Alice and Bob cannot be selected together. 2) Charlie must be selected if David is selected. 3) Eva can be selected only if Alice is not selected. Which of the following groups satisfies all the conditions?

D. BOB, CHARLIE, EVA

From a set of items: P, Q, R, S, and T, the following selection rules apply: 1) P cannot be selected if Q is selected. 2) R must be included if S is included. Which of the following selections is valid?

B. Q, R, T

A box contains red, blue, and green balls. If there are twice as many red balls as blue balls and three times as many green balls as red balls, which color has the least number of balls?

B. BLUE

A team of four members is to be formed from the following candidates: P, Q, R, S, and T. The selection criteria are: 1) P and Q cannot be selected together. 2) R must be included if S is included. 3) T can be included only if P is not included. Which of the following combinations meets the selection criteria?

C. Q, R, S