An single LAN segment can only have one default gateway.
A PC can be connected to more than one LAN segment.
A single physical LAN segment can have more than one logical, or virtual, LAN segments operating on it.
Absolutely not. Think about it from a purely logical perspective. It's an oxymoron. How can you have multiple defaults? The whole point of a default is to eliminate ambiguity. It's not a default if it still requires a decision be made.
Given multiple default gateways, Windows will only ever use one and ignore any others (usually based on which has the higher priority connection).
If the question is limited to whether a PC can *literally* have multiple default gateways, the answer is yes, in the sense you can have multiple network connections, each w/ its own default gateway. But that misses the point. What matters most (or at least should) is what is the *effect*? As I said before, from the perspective of any PC connected to multiple networks, only ONE of those default gateways is used, the others are IGNORED.
So given that, what’s the right answer? Can a PC have multiple default gateways? I guess it just comes down to how you interrupt the OP’s question. Yes, as in you can configure multiple default gateways, but as a practical matter, no. You can’t have MULTIPLE defaults, it makes no sense from the PC’s perspective.