Q.A trading firm in Nagpur must send an original, signed contract document to a client in another city within 24 hours, and the client has requested proof of delivery. Ordinary post would take several days and offers no tracking. Which communication service should the firm use, and why is it more suitable than ordinary post or a simple phone call for this situation?

An original signed physical document has to travel as a physical object, so a phone call cannot substitute for it — and among the physical-delivery options, one is built specifically for speed, tracking, and proof of delivery. …

The requirement here is specific: an original, signed physical document must reach the client within 24 hours, with proof of delivery.

A simple phone call (a telecom service) cannot fulfil this need at all, because it cannot physically transmit the original signed paper document — it could only be used to inform the client that the document is on its way, not to deliver it.

Ordinary postal service can carry the physical document, but the case explicitly states that it would take several days and offers no tracking, so it fails both the 24-hour deadline and the proof-of-delivery requirement.

A Courier service is designed precisely for this kind of situation: it offers door-to-door pickup and delivery, is generally much faster than ordinary post (well within 24 hours for most in-country destinations), and provides tracking along with proof of delivery (such as a signed receipt) — meeting both of the firm's stated requirements. …

Students sometimes answer 'email' because it is the fastest communication method overall — but the case specifically requires the original signed physical document to be delivered, which only a physical-delivery s …