FIA

Vitamin A deficiency primarily causes night blindness because it impairs the retina's ability to function in low light conditions. This is a well-established fact in nutrition and health science.

Lord Minto served as the Viceroy of India from 1905 to 1910, representing British authority in India during that period. He was not Prime Minister or Secretary of India, making option B the correct answer.

Jupiter is known for its Great Red Spot, a giant storm visible as a dark spot on the planet. This distinguishes it from Saturn and Mercury, which do not have such prominent dark spots.

Section 8 of the FIA Act 1974 pertains to the power of the Federal Investigation Agency to make regulations, not indemnity. Therefore, the correct answer is 'Regulations'.

Under the FIA Act and related laws, rewards are typically given to both members (officers or agents) and the public who assist in investigations or provide valuable information. Therefore, 'Members and the public' is the correct answer.

The sum of the first n positive odd integers is n squared. For n=50, the sum is 50² = 2500. However, the options given do not include 2500 as the correct sum. Actually, option B is 2500, which matches the correct sum. Therefore, the correct answer is B, not A. The original correct_answer was B, which is correct. The explanation was missing, so it has been added.

According to the Federal Investigation Agency (FIA) Act of 1974 and related rules, the legal functions such as prosecution and legal advisory roles within the FIA are typically fulfilled by the Public Prosecutor. The FIA is headed by a Director General who has police powers, but the legal matters are handled by the Public Prosecutor. Therefore, the correct answer is option B, Public Prosecutor.

The slogan "Make America Great Again" was popularized by Donald Trump during his 2016 presidential campaign, making option B the correct answer.

The current President of China is Xi Jinping. The other options are incorrect names or fictional.

The unit of electric current is the Ampere, which measures the flow of electric charge per second. Joule is a unit of energy, and Watt is a unit of power, so they are incorrect in this context.