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Solution

Minimum number of straight lines required = 16.

Counting line-wise:
Horizontal lines = 3
Top horizontal = 1, middle horizontal = 1, bottom horizontal = 1

Vertical lines = 4
Left side = 1, right side = 1, two inner verticals = 2

Slant lines = 9
Left upper outer slant = 1
Left upper inner slant = 1
Right upper inner slant = 1
Right upper outer slant = 1
Left lower outer slant = 1
Left lower inner slant = 1
Right lower inner slant = 1
Right lower outer slant = 1
Middle top-to-bottom slant/straight connection counted = 1

Total = 3 + 4 + 9 = 16

Hence, the minimum number of straight lines is 16. Final Answer: (a) 16