Change color of only specific legends/bars in HTML5 Bar charts.

I have a fully fucntioning HTML5 bar chart with different categories. I want to change the color of a specific bar

For example, This bar misses the month name and i want to change the color of this specific bar to any different color without changing the color of my other bars and series. Here, Month is a category whose value is null in this particular case and that is why i am printing it as "NA".

I am stuck with this problem for days. Please, Help me out here. Let me know if i am supposed to provide more details. 

Thanks.

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