What is the difference between "until end of (phase/step)" and "until (phase/step)"?

The correct answer highlights the distinction in timing indicated by the phrases "until end of (phase/step)" and "until (phase/step)."

When a card effect states "until end of (phase/step)," it means that the effect will apply continuously throughout the entirety of that phase or step and will cease to apply only when that phase or step concludes. For example, if an effect lasts "until end of your turn," it remains in play until your turn is over, which includes all phases and steps within that turn.

On the other hand, "until (phase/step)" refers to a specific moment before that phase or step begins. For instance, if an effect states "until your next upkeep," it will terminate right before your next upkeep begins, meaning it is still in effect during your turn but stops when you reach your next upkeep step.

This difference is crucial for understanding how long effects last and when they actually end, impacting gameplay decisions based on timing. The other options either misinterpret the relationship between the beginning and end of phases or misconstrue how these terms apply in a turn, which is why they do not accurately explain the relationship between these two phrases.