Assertion: An amalgam is a material formed by the reaction of mercury with another metal.
Reason: Almost all metals can form amalgams with mercury. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore.
A. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion.
B. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
C.Assertion is correct but Reason is incorrect
D.Both Assertion and Reason are incorrect

Hint: Almost all the metals can form amalgams with mercury. Amalgams are used in dentistry and for the extraction of gold from ores.

Complete step by step solution:
Here, in the Assertion, An amalgam is a material formed by the reaction of mercury with another metal, which is true. Almost all the metals can form amalgams with mercury. Amalgams are used in dentistry and for the extraction of gold from ores.
In the Reason, silver-mercury amalgams are important in dentistry also the gold-mercury amalgam is used in the extraction of gold from ore.
So here, Both Assertion and Reason are correct and Reason is also the correct explanation of the Assertion.

Hence the correct option is A.

Additional information:
Most of the ingot can make amalgams with mercury. Which are beneficial in density and for the purification of gold from ore.

Note:
An amalgam is material compost by the reaction of mercury with other metals. Maximise all the metals can obtain amalgams when fused with mercury, the remarkable exception being iron. Silver-mercury amalgams are beneficiary for dentistry, and gold-mercury amalgam is utilized in the purifying of gold from ore.