Which of the following ores is a mixed oxide of two different metals?

$A$ mineral is called an ore if

Of the following substances,the one which does not contain oxygen is:

Sulphide ion is a soft base and its ores are common for metals. Which of the following metals commonly occur as sulphide ores?
$(a)$ $Pb$ $(b)$ $Al$ $(c)$ $Ag$ $(d)$ $Mg$
Choose the correct answer from the options given below:

Which one of the following ores is a chloride?

Which of the following is not an iron ore?