Let A $=\{0,1,2,3,4,5,6,7,8,9,,.\}$ be the alphabet. The

grammar is defined as follows:

F $=-$ FN $|$ FN

FN $=$ N $|$ N $.$ N

N $=$ D $|$ D$,$ N

D $=0|1|2|3|4|5|6|7|$

$8|9$

The different symbols here are all abbreviations: F is the entity to be defined, FN is a

fractional number, N is a sequence of digits, and D is a digit. Which of the following

strings are produced by the grammar?

$1.5\mathrm{.}26$

$2.-7\mathrm{.}77$

$3.3.-14$

$4.4-5\mathrm{.}16$