Explanation:

- An arithmetic progression (AP) is a sequence of numbers where each term after the first is found by adding a constant, called the common difference.

- The formula for the nth term of an AP is $a_n=a+(n-1)\cdot d$, where $a$ is the first term and $d$ is the common difference.

- Here, the first term $a=4$ and common difference $d=4$.

- Therefore, the 50th term $a_{50}=4+(50-1)\cdot 4=4+196=200$.

- The arithmetic mean of an entire sequence is the average of the first term and the last term. This formula is $(a_1+a_{50})/2$.

- So, the mean is $(4+200)/2=102$.

Option 4: 102