In reference to the Object Identifier tree
a. What do you expect the subject of the standard 1.2.840.113549 to be? (Make a guess).
Here are the answers for the questions.
A. As per the ASN Oid tree given, the subject matter would be related to ISO Member body as 1.2 comes to IS0->ISO Member body
Solution clearly explains with an example about identifying OID from Object Identifier Tree represented in ASN.1