when you are in a city without a garage neither are an option though
depends on your setup. I happen to be locked down far away from home, with my car in the street. I run a very long extension cord from the home, across the sidewalk, up to the car and let my battery charger charge the battery for x hours every week or so. I cannot really remove the battery: car requires a visit to the dealership after a battery change (total ripoff but that's how it is: fancy luxury car). Well, technically it's possible to place a new battery in while letting the old battery connected at all times, but it's a bit tricky to do. So I really really don't want to have my battery die during this lockdown.
My battery charger/maintainer (CTEK, quite common amongst petrolheads) shows an arbitrary 8 levels of "charge" and car was down to 3 out of 8 after two weeks of lockdown (I requires to be at 4 out of 8 for the car to start). After two hours of charge it's back to 5 out of 8.
Wires are thin, so I can close the trunk with the charger outside the car (and due to the plug, it's not possible to steal the charger without cutting the charger's cord, so I'm not too concerned about theft).