In the following sets of resonance forms, label the major and minor contributors and state which structures would be of equal energy. Add any missing resonance forms.
`[CH_(3) - overset(O)overset(||)C- overset(-)CH - overset(O)overset(||)C - CH_(3) hArrCH_(3) - overset(O^(-))overset(|) C = CH - overset(O)overset(||)C - CH_(3)]`

Explanation

To solve the problem of identifying major and minor resonance contributors and determining equal energy structures, we will follow these steps:

### Step 1: Identify the Given Resonance Structures
We have the following resonance structures:
1. Structure 1: \( CH_3 - O=C - CH^{-} - O=C - CH_3 \)
2. Structure 2: \( CH_3 - O^{-} - C = CH - O=C - CH_3 \)

### Step 2: Draw the Missing Resonance Form
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