Some may think that mesomeric structures be ‘real’, that molecules ‘resonate back and forth between them, like a pendulum’ or that there be any type of ordering within mesomeric structures.
All of that is not the case. Mesomeric structures are our crutches to understand what is only one state of the molecule. We draw them in a line interconnected by a series of mesomery arrows because we are uncapable of drawing multi-dimensionally. There is no ‘first’ or ‘later’, no ‘full single’ or ‘full double’ bond. You must understand that all those structures are equal and equally far from reality. Reality is much closer to a continuous wave function with electron deficiencies on the benzylic, ortho and para carbons, with varying (but constant for a given bond) bond orders somewhere between 1 and 2.
Your question in its original form is basically moot. However, a marking scheme of your exam may require you to draw five mesomeric structures rather than just four to get full marks. That is up to your teaching staff.