When selecting an electrode with a designation of E7018 what does the first letter(E) indicate?(Multiple Choice) a) Arc welding electrode. b) Minimum tensile strength of deposited weld metal in ksi. c) Welding positions of usability. d) Electrode covering type and type of current.

The correct answer is:<br /><br />a) Arc welding electrode.<br /><br />Explanation: In the designation $E7018$, the first letter "E" indicates that it is an electrode used for arc welding. The subsequent numbers and letters provide additional information about the electrode's properties and characteristics.