Look at the example printed under the blank box. Ask whether that substance is a metal, and whether the option you pick would overlap with the two branches already shown.
In a classification chart, branches at the same level must be of the same kind and must not overlap.
Testing each option against that rule rules out three of them without any factual recall.
Step 1: Apply the no-overlap rule to option (B).
Ferrous and non-ferrous are already two of the three branches, and both are kinds of metallic mineral. Putting metallic beside them as a third branch would repeat what the first two already cover.
Option (B) fails on logic alone.
Step 2: Apply the same rule to option (C).
Precious minerals such as gold, silver and platinum are also metals, so this branch too would sit inside the metallic group rather than beside it.
Step 3: Use the example to decide between the last two.
The example given is sulphur. Energy minerals are coal, petroleum and natural gas, and sulphur is not one of them, so option (D) does not fit.
Step 4: Confirm the surviving option.
Sulphur sits with mica, salt, potash, limestone, granite, marble and sandstone in the non-metallic group, and non-metallic is the one branch that does not overlap with ferrous and non-ferrous.
