Which of the following is the standardized mark on jewellery?

ISI FSAAI Hallmark FPO

Hallmark

In 1928, the company introduced the brand name Hallmark, after the hallmark symbol used by goldsmiths in London in the 14th century, and began printing the name on the back of every card. That same year, the company became the first in the greeting card industry to advertise their product nationally.