Which one of the following rivers is well known for having a cuspate (tooth shaped) delta at its mouth?

Introduction / Context:
Deltas are landforms created where rivers deposit sediment as they enter a standing body of water such as a sea or lake. They have different shapes depending on the balance between river flow, waves and tides. A cuspate delta has a pointed, tooth like form. This question asks which river among the options has such a delta at its mouth.

Given Data / Assumptions:

• The term cuspate delta refers to a delta that projects into the sea with a more or less pointed, triangular shape, often created where strong waves spread the sediment symmetrically.
• The rivers listed are the Mississippi, Niger, Nile, Tiber and Ganges.
• We must match the characteristic cuspate shape with the correct river.
• We assume the standard examples used in physical geography textbooks.

Concept / Approach:
Different deltas have characteristic shapes. The Mississippi River delta is often described as a bird foot delta, with several long distributaries extending into the Gulf of Mexico. The Nile delta is more arcuate or fan shaped. The Ganges Brahmaputra delta is huge and highly irregular. The Niger delta is also complex. The Tiber River delta near Rome is a classic example of a cuspate delta where wave action has shaped the river mouth into a more symmetric, tooth like projection into the sea.

Step-by-Step Solution:
Step 1: Recall the standard classification of deltas: bird foot, arcuate, cuspate and estuarine, among others.Step 2: Associate each major river with the type of delta that geography books normally mention. The Mississippi is bird foot, the Nile is arcuate and the Ganges Brahmaputra is a large, tide influenced delta.Step 3: The Niger delta is wide and oil rich but is not usually used as the textbook example of a cuspate delta.Step 4: The Tiber River delta at the coast near Ostia in Italy is cited as a classic cuspate delta, where wave action redistributes sediment on both sides of the river mouth.Step 5: Therefore, among the options, the river with a cuspate delta is the Tiber.

Verification / Alternative check:
Physical geography references often provide diagrams showing the Mississippi as bird foot and the Tiber as cuspate. These diagrams highlight the difference between a delta with elongated distributaries and one that has a more pointed, symmetric plan shape. The location near Rome and the historical port of Ostia are often mentioned when describing the Tiber delta, supporting its identification as cuspate.

Why Other Options Are Wrong:
The Mississippi River delta does not form a simple triangular tooth shape but instead has several finger like projections, giving it the bird foot label. The Niger and Ganges Brahmaputra deltas are broad and complex, influenced by tides and river flow, not forming the neat cuspate outline. The Nile forms a more rounded arcuate delta. None of these match the classic cuspate form described in textbooks.

Common Pitfalls:
Many learners remember only that Mississippi has a special type of delta and may mistakenly connect it to cuspate instead of bird foot. Others may think that any triangular looking delta could be described as cuspate without recalling the precise classification. To avoid confusion, link the names carefully: Mississippi bird foot, Nile arcuate, Tiber cuspate. This simple mapping helps to select the correct answer quickly.

Final Answer:
The river known for having a cuspate delta is the Tiber River.