The student in charge of the experiment wishes to present his/her findings in support of the theory that motor imagery and action observation together facilitate a greater increase in motor excitability than either protocol alone.
which of the following would be the best reason to withhold this presentation?

a. the procedure used did not include mep recordings prior to each task.
b. mep amplitudes in an individual are typically highly consistent.
c. the motor tasks performed in the experiment were too simple.
d. the six different conditions were run in random order.

C. The motor tasks performed in the experiment were too simple.

On this case is the best option since the student wants to explain the effect of motor imagery and action observation together into the excitability. And maybe is too simple, since we need to cover other possibilities in order to analyze the excitability.

Explanation:

A. The procedure used did not include MEP recordings prior to each task.

Not true, is not a requisite record MEP prior to the task to evaluate the variable of interest on this case.

B. MEP amplitudes in an individual are typically highly consistent.

The Motor evoked potentials (MEP) "are electrical signals recorded from neural tissue or muscle after activation of central motor pathways". But on this case that's a technical aspect related to the topic and this not would be the reason why we need to withhold the presentation

C. The motor tasks performed in the experiment were too simple.

On this case is the best option since the student wants to explain the effect of motor imagery and action observation together into the excitability. And maybe is too simple, since we need to cover other possibilities in order to analyze the excitability.

D. The six different conditions were run in random order.

That's not true the student are not analyzing 6 different conditions, just 2.

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.