I'm working through a logical reasoning problem and am stumped on why the provided answer is correct. I've laid out the premises and my own logical deduction, which points to a different answer. I'd appreciate it if someone could point out the flaw in my reasoning.
Here is the question stem:
Hypothesizing that lullabies, characterized by their slow tempos, are universally calming to infants, Constance M. Bainbridge and colleagues played a lullaby sung in the Scottish Gaelic language and a non-lullaby sung in the Seri language to a group of infants.
The team found that the infants' heart rates decreased more during the lullaby than during the non-lullaby. Since a decrease in heart rate is associated with relaxation, the team concluded that the lullaby relaxed the infants.
Noting that reduced heart rate can also be associated with increased attention, one critic argues that instead, the lullaby simply attracted the infants' attention. Bainbridge and colleagues also measured pupil size, as pupils typically become larger when a stimulus captures a person's attention.
Question:
Which finding, if true, would most directly weaken the critic’s claim?
A. Blinking, which indicates attention, was equally frequent whether infants were listening to the song in Scottish Gaelic or song in Seri.
B. Neither the Scottish Gaelic language nor the melody of the traditional Scots lullaby was familiar to infants in the study.
C. The infants' pupils were smaller when the infants were listening to lullabies than when they were listening to non-lullabies.
D. Parents of infants in the study chose the lullaby over the non-lullaby when asked which song they would use to calm their child.
The correct answer is supposedly A, but I can't understand why. My analysis points squarely to C as the most direct rebuttal.
Below is my attempt at this problem:
Let L represent "The infants were listening to the lullaby."
Let A represent "The infants' attention was attracted."
Let P represent "The infants' pupils were larger."
Premise 1: L → A (If Lullaby, then Attention)
Premise 2: A → P (If Attention, then Larger Pupils)
Logical Conclusion: L → P (Therefore, if Lullaby, then Larger Pupils)
For the critic to be right, it must be true that listening to the lullaby causes pupils to become larger.
Option C provides exactly the evidence required to weaken the claim. Option C shows that when L was true, P was false. In fact, Option C shows something even stronger: the opposite of P occurred.
Symbolically, Option C demonstrates that L → ¬P. Hence, I believe that the correct answer must be C and not A.
Could someone use formal logic (if necessary) to verify whether the correct answer is A or C?