Explanation:

Let’s walk through this, step by step:

- The question gives us a code language, swapping month names.

- February is called March.

- March is called April.

- April is called June.

- June is called September.

- September is called November.

- The question asks: which “month” (in the code) has the most days? We need to map the *real month* with 31 days back through the code.

- The real month with the most days is March (31), May (31), July (31), August (31), October (31), and December (31). But among the options, let's check where 31 days can land.

- Looking at the coding: March (in code) = real February (28/29); April (in code) = real March (31); June (in code) = real April (30); September (in code) = real June (30); November (in code) = real September (30).

- From the options:

- Option 1: September (in code) actually stands for real June (30 days).

- Option 2: March (in code) stands for real February (28/29 days).

- Option 3: April (in code) stands for real March (31 days).

- Option 4: June (in code) stands for real April (30 days).

- Here’s the thing: Out of all these, only April (in the code, really March) has 31 days.

So, the correct answer is:

Option 3: April