### Solution:

Concept- Roman Numerals of 73 is LXXIII.The rules for writing roman numerals must be remembered, and they are the same as the rules for writing English numerals, which are 1, 2, and 3. It will be simple to write roman for larger numbers if we first learn the principles for romanizing numbers from 1 to 10.

The roman numbers from 1 to 10 will now be written.

I

II

III

IV

V

VI

VII

VIII

IX

X

In the beginning, we can see that 1 is written as I, 5 as V, and 10 as X.

Two and three are clearly written, however we can see that I is written on the left side of V for four. Writing I on the left therefore equals 5, or 1 less than V. This can be generalized by saying that writing an alphabet next to another letter on the left implies subtracting that value, and writing it on the right means adding that value. However, the value being added or subtracted cannot be bigger than the value being added to or subtracted from.

Again, the numbers 6, 7, 8, 9, and 10 fall under this criteria.

To add 1 to 5, write I to the right of V. The same is true for numbers 7 and 8, however for number 9, writing I to the left of X means deducting 1 from 10.

However, we must use caution when drafting this rule since while we can write 7 as VII, we cannot write 8 as IIX.

Similar to how 1 is written as I and 10 as X, 50 is written as L, 100 as C, and 1,000 as M.

Now let's use these guidelines to write 73 in roman characters.

As in 7, adding 20 to 50 results in 70 being written as LXX, and we now add 3 by writing LXXIII.

Hence, the correct answer is LXXIII.