How to align a text inside a plot?

Questions
1

Hi,
I have a text to be aligned inside a plot at a desired location (top right).
I used the Show command followed by Graphics and Text. But I’m unable to take my text to the location.

in my code the text is “(b)” which is to be brought to the top right location.

My code:

y = Range[1, 10];
x = Range[1, 10];
visco = 12*10^-6;
x = -p22*(1/xi - I k);
y = (-q11*(1/xi - I k) - 
     x*(q22*(1/xi + I k) - q33*(1/xi + I k)*(I k - 1/xi) - 
        q44*(1/xi^2 + k^2) - q55*(1/xi - I k)))/(p22 + 
     p33*(I k - 1/xi) - p55*(1/xi^2 + k^2));
y = y*10^-21;
Show[Plot[{Im[y] /. {xi -> 100}, Re[x] /. xi -> 50, 
   Re[x] /. xi -> 10}, {k, 0, 100}, PlotRange -> All, 
  PlotStyle -> {Directive[Red, Thick], Directive[Blue, Dashed, Thick],
     Directive[Black, Thick, Dashed]}, Frame -> True, 
  FrameStyle -> Directive[Black, Thickness@0.0125], 
  PlotLegends -> 
   Placed[LineLegend[{Style["\[Xi] = 100", Bold, 14], 
      Style["\[Xi] = 50", Bold, 14], Style["\[Xi] = 10", Bold, 14]}, 
     LegendFunction -> None, LegendLayout -> "Column"], {Left, Top}], 
  FrameLabel -> {"K", 
    "\!\(\*SubscriptBox[\(\[CapitalOmega]\), \(i\)]\)"}, 
  LabelStyle -> Directive[Black, Bold, 14], RotateLabel -> True, 
  AspectRatio -> 0.5, 
  FrameTicks -> {{Charting`ScaledTicks[{10^9 # &, #/10^9 &}], 
     None}, {Automatic, None}}], 
 Graphics[Text[Style["(b)", FontSize -> 14, Black], {97, 97}]]]

Kindly advice.

Rgds.

2

This is a way:

Text[Style["(b)", FontSize -> 14, Black], Scaled[{1, 1}], {1, 1}]
3

Thanks, the text is getting to the desired location i.e. to the right top corner of the plot.
Now, I tried to scale the coordinates so as to get the text to left top, or to the centre top. I changed the coordinates to (-1,-1) or (0,1) etc. But its not going there.

4

The scaled coordinates range from 0 to 1. Left top is {0,1}, center top is {.5,1}. Then you may have to adjust the offset:

Text[Style["(b)", FontSize -> 14, Black], Scaled[{0, 1}], {-1, 1}]
Text[Style["(b)", FontSize -> 14, Black], Scaled[{.5, 1}], {0, 1}]

Confusingly enough, the offset range is from -1 to 1.