Select which ones of the following equalities are correct and would be useful to establish that log₂x and log₁₀x are of the same order:
a) log₂x = log₁₀x / log102
b) log₂x = log₁₀x / log210
c) log₂x = log₁₀x * log102
d) log₂x = log₁₀x * log210