Option 1: Iron and Steel industry

This option suggests that the major beneficiary of the Mumbai port is the iron and steel industry. However, there is no evidence or information provided to support this claim. Therefore, it is not a correct answer.

Option 2: Sugar and Cotton textile industry

This option suggests that the major beneficiary of the Mumbai port is the sugar and cotton textile industry. Again, there is no evidence or information provided to support this claim. Therefore, it is not a correct answer.

Option 3: Cotton textile and Petrochemical industry

This option suggests that the major beneficiaries of the Mumbai port are the cotton textile and petrochemical industry. This is the correct answer provided in the question. The Mumbai port is known for its export of cotton textiles and import of petrochemical products, making these industries major beneficiaries of the port.

Option 4: Engineering and Fertilizer industry

This option suggests that the major beneficiary of the Mumbai port is the engineering and fertilizer industry. However, there is no evidence or information provided to support this claim. Therefore, it is not a correct answer.

In conclusion, the correct answer is option 3: Cotton textile and Petrochemical industry.