Planet having the longest day _______.

Explanation

To determine which planet has the longest day, we need to understand what "longest day" means in terms of planetary rotation. The longest day refers to the time it takes for a planet to complete one full rotation on its axis. Here’s how we can arrive at the answer step by step:

### Step 1: Understand the Concept of a Day
A "day" on a planet is defined by the time it takes for that planet to rotate once on its axis. This rotation determines how long one side of the planet is exposed to sunlight (daytime) and how long it is in darkness (nighttime).

**Hint:** Remember that a planet's day length is related to its rotation period.

### Step 2: Identify the Planets
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