Boolean algebra is essentially based on:
A) Symbols
B) Logic
C) Truth
D) Numbers

Hint: To solve this we should first understand the basics of Boolean algebra. We use symbols to represent logic to interpret and calculate, a truth table to understand the outcome, and numbers like $1$ and $0$ to represent high and low.

Complete step by step solution:
First of all, let’s start with what Boolean algebra is.
Boolean algebra can be defined as a branch of algebra which gives the result as $1$ and $0$ for truth and false respectively.
While solving questions with Boolean algebra,
1. We use symbols just to represent the type of connection in a given circuit. We can use the standard symbols to remember the type of connection.
2. Logic is very important in Boolean algebra as it decides the result we will get after an operation. We can say Boolean algebra is built upon logic. There are two logic levels, high and low. A Higher level represents truth or we can say the value is higher compared to another. A lower level represents false or the value is lower than the other value.
3. The truth table only represents the values of the logic or the output due to different combinations of the logic gate.
4. Numbers are not important in Boolean algebra. They are only used to represent highs and lows for logic.
Hence from the above discussion, we can say that logic is the most important part of Boolean as it is entirely made up of logic. So we can conclude that option (B) is the answer.

Note: Boolean algebra is mostly used in digital gates and circuits. We generally use the different laws of Boolean algebra i.e. Distributive law, Commutative law and Associative law to simplify Boolean expression and make the calculation easier.