I think the answer to the top one is b and on the second one d
In the study of history the available documents for studying a certain period is unchanging over time.
Option: B
Explanation:
History is the study of events and phenomena over space and time. Space means where the particular incident is taking place. Time means the period of occurrence of particular event. A certain period suppose the period of sultanate or mughal empire requires some documents, records to be studied in detail.
And these available documents, records can never be changed over time. History is study of things over changing space and time. Archaeological evidences also keep some valid documents for studying historical events.
A gentlemen's agreement or gentleman's agreement is an informal and legally non-binding agreement between two or more parties. It is typically oral, though it may be written, or simply understood as part of an unspoken agreement by convention or through mutually beneficial etiquette. The essence of a gentlemen's agreement is that it relies upon the honor of the parties for its fulfillment, rather than being in any way enforceable. It is, therefore, distinct from a legal agreement or contract, which can be enforced if necessary
