What is the correct way to name the straight angle in the figure below?

Naming angles (video), Angle introduction

Straight Angles

Angle Classification

How to Name an Angle: 11 Steps (with Pictures) - wikiHow

Naming angles (video), Angle introduction

Angles in triangles and quadrilaterals - KS3 Maths - BBC Bitesize

How to Name an Angle: 11 Steps (with Pictures) - wikiHow

Angle – Definition and Types with Examples

Irregular Polygon - Math Steps, Examples & Questions