The value of the velocity of light $c$ used in SI definitions is—

• a$2.99{,}792{,}458 \times 10^6$ m/s
• b$2{,}99{,}792{,}458$ m/s
• c$3 \times 10^{10}$ m/s
• d$1.602 \times 10^{8}$ m/s