A level Edexcel physics aluminium foil passing through a uniform field

Hello, I’m self teaching A level physics and I have gotten stuck on question 8 of this pmt worksheet and I’m not quite sure why the answer would be C. I thought it may be to do with the electrons within the aluminium sheet experiencing lorentz force at one end as it enters and exits causing it to slow down but I’m not quite sure and couldn’t find clarification anywhere else and was wondering if maybe someone could help provide some clarification.

https://pmt.physicsandmathstutor.com/download/Physics/A-level/Topic-Qs/Edexcel/07-Electric-and-Magnetic-Fields/Set-N/Magnetic%20Fields%20and%20Alternating%20Current%20%28MCQ%20Only%29.pdf

It has to do with Faraday's law of induction and Lenz's law.
These 2 laws should be found in your text or notes if not, then you have not learnt them.

What this question is doing is distinguishing between a moving charge on a magnetic field which produces a force perpendicular to both the motion and the magnetic field. In this case, that force will be perpendicular to the page and so will result in no force (acceleration) along the air-track. However, in a changing magnetic field will create a force on a charge, the direction of which always opposes the thing that causes the force. I.e, always a deceleration. The unstated assumption here is that the magnitude of the magnetic field is insufficient to stop the air track working by pushing the slider such that it touches the surface.

The force on a charge (inside the conductor) is at right angles to the field and the motion so in this case would be a vertical force. The force in a changing field would be parallel to the motion.