Select the pair of isobars from the following species:
`""_(17)^(37) A, ""_(17)^(35)B,""_(18)^(37) C ,""_(18)^(36)D, ""_(19)^(38)E`

Options

A. A and B
B. A and C
C. C and E
D. C and D

Explanation

To solve the question of identifying the pair of isobars from the given species, we need to follow these steps:

### Step 1: Understand the Definition of Isobars
Isobars are atoms that have the same mass number (A) but different atomic numbers (Z). The mass number is the sum of protons and neutrons in the nucleus.

### Step 2: List the Given Species with Their Mass Numbers
We need to extract the mass numbers from the given species:
- A: \( _{17}^{37}A \) → Mass number = 37
- B: \( _{17}^{35}B \) → Mass number = 35
- C: \( _{18}^{37}C \) → Mass number = 37
- D: \( _{18}^{36}D \) → Mass number = 36
- E: \( _{19}^{38}E \) → Mass number = 38

### Step 3: Compare the Mass Numbers
Now we will compare the mass numbers of the species to find pairs that are the same:
- A (37) and B (35) → Different mass numbers
- A (37) and C (37) → Same mass numbers
- A (37) and D (36) → Different mass numbers
- A (37) and E (38) → Different mass numbers
- B (35) and C (37) → Different mass numbers
- B (35) and D (36) → Different mass numbers
- B (35) and E (38) → Different mass numbers
- C (37) and D (36) → Different mass numbers
- C (37) and E (38) → Different mass numbers
- D (36) and E (38) → Different mass numbers

### Step 4: Identify the Isobar Pair
From the comparisons, we see that:
- A and C both have a mass number of 37.

Thus, the pair of isobars is **A and C**.

### Final Answer
The pair of isobars from the given species is **A ( \( _{17}^{37}A \) ) and C ( \( _{18}^{37}C \) )**.

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