Final answer:
The correct option is (b). Top shoulder. The flat iron steak is cut from the top shoulder area of the cow, specifically from the top blade muscle of the chuck.
Step-by-step explanation:
The flat iron steak is a relatively new cut of beef that is known for its tenderness and flavor, which makes it a popular choice for grilling. The flat iron steak is actually cut from the top shoulder area of the cow, specifically from the top blade muscle of the chuck.
It's located just above the shoulder blades, hence the term "flat iron" - resembling the old metal flat irons used to press clothes. This is also one of the reasons this steak is sometimes referred to as a top-blade steak.