It is given that "R is a many-to-one relationship from entity set E1 to entity set E2"
E1------N-------R---------1-------E2
Therefore,
Participation of E1:=1
Cardinality of E1:=1
Participation of E2:=1
Cardinality of E2:=N
Therefore, Answer is (A): Every entity in E1 is associated with exactly one entity in E2 because the number of relationships in which an entity of a entity type E1 can participate is equal to 1.
Note: "Cardinality of a set/Entity set" is a different thing and "Cardinality of an Entity in a relationship" is a different thing.
Cardinality of a set/Entity set: Number of instances/elements in that set.
Cardinality of an Entity in a relationship: Maximum number of relationships in which an entity of a given entity type can participate.
Therefore, the line "cardinality of E1 is greater than the cardinality of E2" just means that the number of instances/entities in E1 is more than the number of instances/entities in E2