The taste of Acid is Sour, that of Base is Bitter and salt is salty. So, Pickle and Lemons give sour taste due to presence of Acids. The sour taste of Lemon is due to presence of Citric Acid in it. While the sour taste of Pickle is due to presence of Vinegar (5% Acetic Acid Solution). Vinegar is mainly used to prevent the Pickle from Bacterial Attack.
An atomic mass unit is defined as a mass equal to one twelfth the mass of an atom of carbon-12. The mass of any isotope of any element is expressed in relation to the carbon-12 standard. For example, one atom of helium-4 has a mass of 4.0026 amu. An atom of sulfur-32 has a mass of 31.972 amu.
Your answer is C for sure