Following is a matrix of certain entries. The entries follow a certain trend row-wise.

Choose the missing entry (?) accordingly.

7B	10A	3C
3C	9B	6A
10A	13C	?

The correct option is 3B.

To find the missing entry in the matrix, we need to analyze the trend row-wise for both the numerical values and the letters.

1. Numerical Trend (Row-wise):

Let us look at the numbers in each row:

In the first row: 7, 10, and 3.
Notice that: $7+3=10$ (or $10-7=3$).

In the second row: 3, 9, and 6.
Notice that: $3+6=9$ (or $9-3=6$).

In the third row: 10, 13, and ?.
Following the same relationship, the middle number is the sum of the first and third numbers: $10+\text{?}=13$

Solving for the missing number: $\text{?}=13-10=3$

2. Letter Trend (Row-wise):

Each row contains a set of the letters A, B, and C exactly once, but in different orders:

First row contains: B, A, C (contains A, B, C)

Second row contains: C, B, A (contains A, B, C)

Third row contains: A, C, ?

Since 'A' and 'C' are already present in the third row, the missing letter must be B.

Combining the missing number (3) and the missing letter (B), the complete missing entry is 3B.