What will come in the place of question (?) mark in following the question:

$90.5+30.1-5.4+?=120.3$

The correct option is 5.1.

To find the value that should replace the question mark (?), we set up the given mathematical equation:

$90.5+30.1-5.4+?=120.3$

Step 1: Simplify the numerical terms on the left-hand side of the equation.

First, add the first two decimal numbers:
$90.5+30.1=120.6$

Next, subtract $5.4$ from the sum:
$120.6-5.4=115.2$

Now, substitute this simplified result back into the equation:
$115.2+?=120.3$

Step 2: Isolate the question mark (?) by subtracting $115.2$ from both sides of the equation:
$?=120.3-115.2$

Performing the subtraction gives:
$?=5.1$

Therefore, the value that should replace the question mark is 5.1.