In Which Case Did Lord Toulson Say

In which case did Lord Toulson say:
The public interest is best served by a principled and transparent assessment of the considerations identified, rather than by the application of a formal approach capable of producing results which may appear arbitrary, unjust or disproportionate.

A) Patel v Mizra [2016]
B) Gray v Thames Trains [2009].
C) Pitts v Hunt [1991]
D) Hounga v Allen [2014]