Write a relational algebra statement to get the Professor name and average score given to each professor, ordered from the highest to the lowest. You can use extended relational algebra $($tau and downwards arrow $)$ for sorting. score$\backslash$table$[[$PID$,$Pname,Papers,Topic$],[109,$Steven,$10,$Java$],[110,$Francis,$50,$Databases$],[111,$Daniel,$40,$Java$],[112,$Joy,$20,$Java$]]$