The open end wrench size for a 3/4 inch American National Standard hex head machine bolt is __________.

Correct Answer: Option C — 1 1/4 inches

Standard American National Standard hex head bolts require specific wrench sizes. A 3/4-inch bolt has a head width across the flats of 1 1/4 inches. Using the correct size prevents rounding the bolt head, ensuring compliance with proper mechanical maintenance procedures for critical shipboard machinery and structural fasteners.